ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Stephen Swaffer on October 01, 2014, 06:23:06 pm

Title: What do you want in a genny?
Post by: Stephen Swaffer on October 01, 2014, 06:23:06 pm
quote author=Nick Enright link=topic=151677.msg1391202#msg1391202 date=1412197264]
I know that the Lincoln model Ranger 305 and Red D Arc GX300 produce a pseudo sine wave output, and that the voltage varies as the load on the welder, and that frequency varies as load on the welder.....

Modern welding is as technical as modern audio, however these welders are designed to weld, and the 120v AC outlets are only designed for construction grade equipment, and NOT for audio equipment. The engineer I spoke with could not guarantee anything when used for audio amplifiers, and definitely not digital gear,.......

[/quote]

The first point only makes sense-any genny (excepting inverters) will do so when hit with a load near its capacity-the assumption would be that it would be unlikely you would be welding during a gig?

On the second point, no offense intended, but even if a welding engineer would guarantee something regarding audio equipment, I am not convinced it would mean a great deal-does he know what they need?

I have no doubt that a Honda inverter would be preferable.  From my POV, there is no way to know if the Lincoln is better than a non-inverter Honda, or any other genny out there because no one publishes meaningful specs-likely because they are not mandated by law, nor are they requested by customers.  No doubt, other genny manufacturers will soon be on the inverter bandwagon-and lower quality ones will become more common.  How do you compare the power quality between two gennys?  If I were designing a genny for audio, what features/benefits would the industry be willing to pay for?

SMPS rectify the input anyway-they should actually work just fine if fed the correct DC voltage,  they would seem to be the least frequency sensitive power supply?
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 01, 2014, 06:33:51 pm
As far as I know there is no inverter generators over 10kw. I think the inverter generators are generally more of toy generators - around 1kw-2kw or less. Good for running somethings like TVs and such but no serious festival or concert could run on that. not to mention festivals need long runtimes offered by bigger generators.

I do know some of the ones we rent monitor the output voltage and "adjust" itself accordingly as the load goes up to keep in within range. I don't think the other gennys do that. No idea about inverter ones as I've never used them.
Title: Re: What do you want in a genny?
Post by: Tommy Peel on October 01, 2014, 07:28:59 pm


As far as I know there is no inverter generators over 10kw. I think the inverter generators are generally more of toy generators - around 1kw-2kw or less.
Looks like the biggest Honda inverter generator is 7kw. I imagine you could run a reasonably powerful, but efficient, PA off of that.
(http://tapatalk.imageshack.com/v2/14/10/01/d5bbd08180a999112de176225b3bc87d.jpg)


Sent from my Moto X (XT1053) using Tapatalk

Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 01, 2014, 08:12:29 pm
As with everything in life.... it depends. Haha.

I ran a 3-over-2 VRX932LAP/918SP rig this past summer on an EU3000is, mains and FOH, and two amps for monitors. I think we ended up later in the day putting stage power on a separate EU2000i (not ground-connected, tho, please don't hit me) when one group was a bit more intense then the others, but beyond that, we made it through. This was for a park event, mild music (not EDM or heavy rock) and no more then 3-400 people at the stage at any one time. VRX was flown in truss (Global Truss ST180s).

-Ray
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 01, 2014, 08:26:11 pm
We're lucky to have an event where someone wants under 8 individual monitor mixes. So we tend to use a lot of power. Yeah I think the local/regional bands around here may have gotten spoiled diva with their monitors somehow. I remember back when 4 monitors was considered plenty.
Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 01, 2014, 09:25:30 pm
We're lucky to have an event where someone wants under 8 individual monitor mixes. So we tend to use a lot of power. Yeah I think the local/regional bands around here may have gotten spoiled diva with their monitors somehow. I remember back when 4 monitors was considered plenty.

Oh, I totally agree. But Tommy mentioned running a powerful and efficient PA off of a Honda-- and I wanted to cite an example where I did just that.

For larger shows, yep, 6-10 mixes and the amps to go along with it. I always brag about having a 45kW WhisperWatt- yeah, I have to maintain it, worry about getting it to events, don't have a backup in case of major failure-- but at the same time, it is a nice feeling that it's a known factor. I know it's condition, that it provides good clean power, that the internal batter is getting old and needs to be jump-started at times (really! Annoying.) -- it's good to know what to expect, when you are responsible for maintenance yourself.

... and I've been able to bail out other companies with it on short notice. :)

-Ray
Title: Re: What do you want in a genny?
Post by: Tommy Peel on October 01, 2014, 10:01:10 pm
I did a gig a while back with an eu2000i with a powered Mackie rig(2 tops, 2 subs, and 3 monitors), FOH, and backline. We had enough SPL for the gig but couldn't get anywhere near FTB. Never tripped the breaker, but I saw the overload light blinking with the music at one point and had to turn down a bit.

Sent from my Moto X (XT1053) using Tapatalk

Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 07:13:56 am
How do you compare the power quality between two gennys?  If I were designing a genny for audio, what features/benefits would the industry be willing to pay for?

SMPS rectify the input anyway-they should actually work just fine if fed the correct DC voltage,  they would seem to be the least frequency sensitive power supply?

SMPSs are impervious to frequency but very susceptible to the voltage distortion created by the very harmonic currents they draw when powered by conventional generators. Because the capacitors in SMPSs draw current only at the peak of the voltage waveform, SMPSs cause a voltage drop at the peak of the waveform, which leads to “flat topping” of the voltage similar to that in the oscilloscope shot below center.

(http://www.screenlightandgrip.com/images/generators/waveform_elec_ballast.jpg)

Left: A non-linear Load powered by Grid Power. Center: A non-linear Load powered by Conventional AVR Power. Right: A non-linear Load powered by Inverter Power.


And since, according to Ohm’s Law, harmonic currents react with impedance to cause voltage drop, the magnitude of this voltage waveform distortion caused by SMPSs is a function of the source impedance. In the case of generators, source impedance is not an easily defined value as generator reactance varies with time following a load change. However, what is certain is that the generator with the lowest internal reactance to an instantaneous current change at a given load will typically have the lowest value of total harmonic distortion under nonlinear load conditions. This is one of the great benefits to using inverter generators over conventional generators: inverter generators have much lower internal reactance and so they are less prone to voltage waveform distortion caused by the harmonic currents drawn by SMPSs. Most generator manufacturers don’t give specifications for internal reactance,  but will give specifications for THD of voltage.

Inverter generators are less prone to voltage waveform distortion because the inverters completely processes the raw power generated by its alternator (converting it to DC before converting it back to AC) –making the AC power it generates completely independent of the engine. In fact, its’ microprocessor controller can vary the engine speed without affecting the voltage or frequency of the power the inverter module puts out. Now that the internal reactance of the engine is separated from the power output, harmonic currents encounter very little impedance; and, as is evident in the oscilloscope shot above right, there is considerably less voltage distortion at the load bus of inverter generators than there are conventional generators. The net benefit is that non-linear loads, like the SMPSs of most electronic equipment, do not adversely affect the power of inverter generators as they do the power of conventional generators. Which means that electronic equipment powered by SMPSs will operate more reliably on inverter generators.

Where there is appreciable voltage waveform distortion created by operating non-linear loads on a conventional generator, other electrical devices operating on the same power are unable to use the distorted waveform effectively. For instance, the SMPSs of electronic equipment depend on the peak value of the voltage waveform to operate effectively. They therefore work sporadically, if at all, on the squared off voltage waveform caused by the harmonic currents they draw encountering the high impedance of power generated by conventional generators. In fact, operating the pseudo square wave of distorted voltage, they will be starved of power.

(http://www.screenlightandgrip.com/images/generators/Ineplicable_Mallfunctions_I.jpg)

Effect of DC Bus Voltage with Flat Topping

Special precautions must be taken with computers and hard drives in particular. The majority of computer based equipment derives its’ internal DC power from AC power switched by a SMPS, or similar power supply, and so it is often here where harmonic problems first arise. As is evident in the illustration above, voltage flat topping from harmonic currents reduces the operating DC bus voltage these power supplies will generate. As a result, the load will be starved of power even though you may read full line voltage with an RMS meter and the power indicator lights light. 
Symptoms to look for are hard drives locking up, internal fuses blowing, and inexplicable malfunctions.

For a more detailed explanation of the electrical engineering principles behind these issues and how to resolve them use this link  (http://"http://www.screenlightandgrip.com/html/emailnewsletter_generators.html") for a newsletter article on  the use of portable generators in motion picture production.

Guy Holt, Gaffer,
ScreenLight & Grip,
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Stephen Swaffer on October 02, 2014, 08:13:32 am

For larger shows, yep, 6-10 mixes and the amps to go along with it. I always brag about having a 45kW WhisperWatt- yeah, I have to maintain it, worry about getting it to events, don't have a backup in case of major failure-- but at the same time, it is a nice feeling that it's a known factor. I know it's condition, that it provides good clean power, that the internal batter is getting old and needs to be jump-started at times (really! Annoying.) -- it's good to know what to expect, when you are responsible for maintenance yourself.


The only things on the Whisper Watt spec sheet that would relate to power quality are frequency reg, voltage and power factor.  I have no doubt the whisper watt is a very good unit-but what is acceptable?  Does the power facto spec adequately address waveform concerns?

The post I mentioned in my OP made the point that welders need consistent performance - ie output.  The interesting thing is that a function block diagram of the ranger has a rectifier creating a DC bus with an output controlled by a microprocessor firing thyristors-in other words it is a large SMPS with a specialized precisely controlled output-but it doesn't seem to mind the voltage/freq variations caused by rpm fluctuations.

I think it was Dick that mentioned watching gear go up in smoke after time.  This makes perfect sense to me with "big iron" gear.  Transformers are frequency dependent and waveform distortion causes heating in transformers and motors.  So a transformer designed to handle "x" watts being pushed to its limits while being fed a distorted waveform can be expected to let the smoke out soon enough.

Perhaps I am being too technical-it just doesn't seem to make sense that a power supply happy with 90-240 vac would be overly sensitive to a gennys output voltage (provided it is not pushing the low end) and waveform?

Maybe I am being over optimistic, but I there seems to be a lot of frustration over getting a proper genny for audio.  Inverters are good-but limited in size.  Then there is always the g-n bond issue.  But nobody is going to spend money to design something unless the have a target customer that knows what they want.
Title: Re: What do you want in a genny?
Post by: frank kayser on October 02, 2014, 10:10:50 am
<snip>

Perhaps I am being too technical-it just doesn't seem to make sense that a power supply happy with 90-240 vac would be overly sensitive to a gennys output voltage (provided it is not pushing the low end) and waveform?
<snip>
Stephen,
Through my inexperience and general electrical ignorance, I arrived at the exactly same question as your too-technical reading.
Great minds run in the same circles ;D   It would be great to understand this apparent inconsistency.
I have been in situations of very overloaded line power where SPMS power supplies were shutting down, but my "big iron" supply was still marching on.
Obviously there's so much more to this than meets the eye...
frank
Title: Re: What do you want in a genny?
Post by: Nick Enright on October 02, 2014, 11:47:34 am

The post I mentioned in my OP made the point that welders need consistent performance - ie output.  The interesting thing is that a function block diagram of the ranger has a rectifier creating a DC bus with an output controlled by a microprocessor firing thyristors-in other words it is a large SMPS with a specialized precisely controlled output-but it doesn't seem to mind the voltage/freq variations caused by rpm fluctuations.


I guess that my original post missed in it's intended statements...

1) I'm sure that the Electrical Engineers that design Lincoln generator-welders could very easily design a pure sine-wave, 60Hz, 120v, ouput on these welders.

2) In my discussion with applications engineers (who I'm sure have a pretty good background in electronics/electricity) they did not recommend using the output of these machines to power audio equipment. AT ALL, welding or not welding.

3) They mentioned that there was no way to tell what the SMPS of some of my equipment would think of the stepped wave power.


There are generators from 7kW (where inverter type go away) up to 640kW. The point is that there are generators already filling this need. There is no need to design a new product...

http://www.whisperwattgenerator.com/

(just one of a few different brands)

These generators are reliable, efficient, quiet, and easy to use.... I'm also a film set electrician, and get to play with single instruments that consume more power than entire stages. (one low budget film overloaded a 1600A gennie, or around 110kVA) they are worth the rental, and if you can keep it rented they can make some cash.




Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 12:46:35 pm
Perhaps I am being too technical-it just doesn't seem to make sense that a power supply happy with 90-240 vac would be overly sensitive to a gennys output voltage (provided it is not pushing the low end) and waveform?

It would be great to understand this apparent inconsistency. I have been in situations of very overloaded line power where SPMS power supplies were shutting down, but my "big iron" supply was still marching on.  Obviously there's so much more to this than meets the eye...

More from my white paper on the use of portable generators in motion picture production (available at http://www.screenlightandgrip.com/html/emailnewsletter_generators.html.) To understand what affect a highly distorted voltage waveform with peak voltage drop would have upon SMPSs it is worth reviewing how the diode/capacitor front end of SMPSs operate.

(http://www.screenlightandgrip.com/images/generators/diode-capacitor_sch.jpg)

Step 1: Rectifier Bridge converts line frequency AC power to rectified sine wave.
Step 2: rectified sine wave is flattened to DC by conditioning Capacitor.

The diode/capacitor section converts AC power to DC by first feeding the AC input through a bridge rectifier, which inverts the negative half of the AC sine wave and makes it positive. The rectified current then passes into a conditioning capacitor/s that removes the 60 Hz rise and fall and flattens out the voltage - making it DC.

(http://www.screenlightandgrip.com/images/generators/Working_of_CFLs.jpg)

Yellow Trace: Rectifier Bridge converts AC power to rectified sine wave. Blue Trace: Stored Capacitor Voltage. Red Trace: Current drawn by capacitors once input voltage is greater than voltage stored in the capacitor (Blue trace.)

As shown in the illustration above, the diode-capacitor circuit only draws current during the peaks of the supply voltage waveform as it charges the conditioning capacitor to the peak of the line voltage. Since the conditioning capacitor can only charge when input voltage is greater than its stored voltage, the capacitor charges for a very brief period of the overall cycle time. Since, during this very brief charging period, the capacitor must be fully charged, large pulses of current are drawn for short durations. Consequently, all diode-capacitor circuits draw current in high amplitude short pulses that roughly coincide with the peak of the voltage waveform.

(http://www.screenlightandgrip.com/images/generators/rectifiedpsuedosquarewaveBW.jpg)

A pseudo square wave after being rectified by a full bridge rectifier

Based upon how diode-capacitor circuits operate, what effect would a "flat topped" voltage waveform exhibiting peak voltage drop (like the one pictured above) have upon loads, like lap tops, camera power supplies and battery chargers, that also utilize SMPSs? If we compare one half cycle of a rectified sine wave to one half cycle of the distorted pseudo square wave generated by non-linear loads, we see that one consequence is that the period during which the capacitors of their SMPSs must recharge is appreciably shortened. Given a shorter interval to charge, the capacitor/s will draw current in even higher amplitude shorter bursts. The diode-capacitor circuit therefore works harder, drawing more current during an even briefer charging period, reducing its power factor and increasing its apparent power or load. As a consequence protective circuit breakers may trip or fuses blow.

(http://[img]http://www.screenlightandgrip.com/images/generators/rectified_capacitor_draw_in.jpg)

Left: half cycle of rectified sine wave. Right: half cycle of rectified pseudo square wave. Blue Line: Minimum Capacitor Voltage. Red Lines denote interval during which current will be drawn by capacitors once input voltage is greater than voltage stored in the capacitor.[/img]

Another adverse effect is that more harmonic currents are generated as less of the power waveform is used by the circuit. In fact, a viscous cycle can get started. The more harmonic currents that are generated, the more distorted the power supplied by the generator becomes. The more distorted the power waveform becomes the more harmonic currents are generated. In this fashion, something akin to a feedback loop can get started until the effect of the harmonics is enhanced to the point where equipment stops working all together.

(http://www.screenlightandgrip.com/images/generators/RectifiedSquareWaveLineComp.jpg)

Blue Line: Minimum Capacitor Voltage. Red Lines denote interval during which current will be drawn
by capacitors once input voltage is greater than voltage stored in the capacitor.

To see why this might happen we have only to compare the pseudo square wave created by 1200 watts of non-PFC SMPS load to that created by 2500 watts of non-PFC SMPS load above. Based upon our discussion of how diode-capacitor circuits operate, we can see in the oscilloscope shot on the right that the peak value of the psuedo square wave created by the 2500W load (after it has be rectified) may not reach a sufficient level to charge the capacitor/s of a power supply. Whether the ballast of a light, or the AC power supply of a lap top, the equipment may be starved of power even though its’ power indicator lights up, and a true RMS voltmeter would indicate about 120 volts on the line. Common symptoms of power starvation are computers locking up, breakers tripping, and HMIs not striking or holding their strike.

(http://www.screenlightandgrip.com/images/generators/waveform_hmi_kino_pkg.jpg)

Same as Above Left: Conventional AVR Power w/ Pkg. of non-PFC Elec. Ballasts & Kino Flo Wall-o-Lite. Center: Scope time base adjusted to
bring elongated waveform back on screen. Right: Inverter Power w/ Pkg. of non-PFC Elec. Ballasts & Kino Flo Wall-o-Lite.

The third frame on the right, is the same package of lights but with power factor corrected electronic HMI ballasts on the EU6500is (an inverter generator.) As you can see, the difference between the resulting waveforms is startling. Even though we are running the same overall load in terms of watts, the fact that the ballasts are power factor corrected, that the power generated by the inverter generator has very little inherent harmonic distortion (less than 2.5%), and that the system impedance is very low, results in virtually no voltage waveform distortion of the power running through the distribution system. For this reason, sensitive electronic equipment running on the same power will continue to operate reliably and effectively without damage even though the overall load on the generator has increased.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Stephen Swaffer on October 02, 2014, 02:08:24 pm



I'm sure that the Electrical Engineers that design Lincoln generator-welders could very easily design a pure sine-wave, 60Hz, 120v, ouput on these welders.

I made almost exactly the same statement in an earlier post.  But engineering and even "electrical engineering" is a very broad subject-I would not expect them to know or even care what a specific device might need.

"There are generators from 7kW (where inverter type go away) up to 640kW. The point is that there are generators already filling this need. There is no need to design a new product..."

With apologies to Ray and no intention to "hit" him, he mentioned using a genny in a pinch that was not "ground connected".  I am not clear if he meant not bonded to rest of gennys or not ground neutral bonded.  G-N bonding is a SAFETY issue and IMO if gennys are not designed and built to make it easy to correctly configure the G-N bond there is lots of room for improvement.  The Whisperwatts (at least some?) have locking switches to select phase/voltage.  Why cannot smaller gennys have a similar system for GN bonding?  As long as users have to use work arounds to properly and safely use a genny-inverter or not-the available designs are not adequate.  While safety  is the end users responsibility-convenient or not, I think it best to make safety convenient whenever possible.

"These generators are reliable, efficient, quiet, and easy to use.... I'm also a film set electrician, and get to play with single instruments that consume more power than entire stages. (one low budget film overloaded a 1600A gennie, or around 110kVA) they are worth the rental, and if you can keep it rented they can make some cash."

Unfortunately, not everyone has the option to use the very best, every time-part of my curiosity is that I am specing home standby generators for a customer as we speak.  The home stand by are "brushless alternator, computer friendly" the larger mobile generators by the same manufacturer are "brushed, superior waveform."  IMO quite the subjective description. The only units they give a THD value are for inverter units-which makes it impossible to compare the power quality of their "portable" "inverter" "mobile" and "home standby " units.  No this is not an offshore bargain basement manufacturer.

I guess I am left relying on "Uncle Dick's" wisdom-I am sure I could do worse. 
Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 02, 2014, 05:06:26 pm
I had two generators, both Honda EU models, powering a stage-- one powering mains/foh/monitors, and the second one was handling stage power. Having not thought about this in the past, should I have a grounding connection between two generators in this case?

-Ray
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 05:19:30 pm
The only units they give a THD value are for inverter units-which makes it impossible to compare the power quality of their "portable" "inverter" "mobile" and "home standby " units.  No this is not an offshore bargain basement manufacturer.

This might help (from Honda Archives):

(http://www.screenlightandgrip.com/images/generators/sinewave_by_gen_type.jpg)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 02, 2014, 05:20:54 pm
I had two generators, both Honda EU models, powering a stage-- one powering mains/foh/monitors, and the second one was handling stage power. Having not thought about this in the past, should I have a grounding connection between two generators in this case?

-Ray

Yes, If there is a difference in the two generators ground potential then you'd have ground loops from the on stage gear. or more importantly hot hazard from the mics or other grounded metal objects on stage where a person could be the ground path between the two grounds that aren't the same voltage. (ex a Mic getting it's ground from the FOH Generator, and a guitar player with his amp/pedal board ground on the stage generator).
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 05:43:39 pm
Having not thought about this in the past, should I have a grounding connection between two generators in this case?

From my IA Grounding/Bonding Workshop:

(http://www.screenlightandgrip.com/images/generators/ProSound_PP_Image_Bonding_Separately_Derived-Systems.jpg)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 05:57:01 pm
There are generators from 7kW (where inverter type go away) up to 640kW.

  Inverters are good-but limited in size.  Then there is always the g-n bond issue.

The new Honda EU7000is can be paralleled for 100A output with the N-G bonded in the paralleling box. They can also be modified to run off a 14 gallon fuel caddy so that they run 20 hours without refueling.

The point is that there are generators already filling this need. There is no need to design a new product...

http://www.whisperwattgenerator.com/

These generators are reliable, efficient, quiet, and easy to use....

And, prone to voltage waveform distortion when supplying non-linear loads.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com

Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 02, 2014, 06:07:10 pm
The new Honda EU7000is can be paralleled for 100A output with the N-G bonded in the paralleling box.

And, prone to voltage waveform distortion when supplying non-linear loads.


Yeah but it only has a 6hour run time at load. Thats why the Stand-by type generators are typically used for festival power.
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 06:11:05 pm
Yeah but it only has a 6hour run time at load. Thats why the Stand-by type generators are typically used for festival power.

They can also be modified to run off a 14 gallon fuel caddy so that they run 20 hours without refueling.

Guy Holt, Gaffer
ScreenLignt & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 02, 2014, 06:14:57 pm
They can also be modified to run off a 14 gallon fuel caddy so that they run 20 hours without refueling.

Guy Holt, Gaffer
ScreenLignt & Grip
www.screenlightandgrip.com

Modified AKA liability. I believe there is a whole thread about that here before. 

http://forums.prosoundweb.com/index.php/topic,150364.0.html
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 06:41:54 pm
Modified AKA liability. I believe there is a whole thread about that here before. 

http://forums.prosoundweb.com/index.php/topic,150364.0.html

No more liability than an MQ Whisperwatt that has been plumbed to draw fuel from an external fuel tank built into the  trailer it is mounted on (the internal tanks are quite small.)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 02, 2014, 08:18:40 pm
No more liability than an MQ Whisperwatt that has been plumbed to draw fuel from an external fuel tank built into the  trailer it is mounted on (the internal tanks are quite small.)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com

That's a trailer that is designed and sold by MQ to do exactly that. Is the 14ga modification that you cite something that Honda designed and sells, or is it a proprietary custom thing? I think purpose designed and built by the manufacturer is a different ballpark then a custom build thing. One would give you the protection of MQ/Honda in case of a failure, the other... wouldn't...

-Ray
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 08:59:39 pm
That's a trailer that is designed and sold by MQ to do exactly that. Is the 14ga modification that you cite something that Honda designed and sells, or is it a proprietary custom thing? I think purpose designed and built by the manufacturer is a different ballpark then a custom build thing. One would give you the protection of MQ/Honda in case of a failure, the other... wouldn't...

My MQ Ultra Silent 60 generator came mounted on a trailer built by Mighty Mover - it was not designed and built by the manufacturer.  The fuel pump modification we do uses Honda original parts in a Honda designed fuel system. It gives you just as much protection as a MQ plumbed to a third party trailer.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Stephen Swaffer on October 02, 2014, 09:38:14 pm
From my IA Grounding/Bonding Workshop:

(http://www.screenlightandgrip.com/images/generators/ProSound_PP_Image_Bonding_Separately_Derived-Systems.jpg)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com

It should go without saying, but if the structures have any kind of metallic path between them (snakes, etc) the bonding really ought to be their as well.
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 02, 2014, 09:39:45 pm
It should go without saying, but if the structures have any kind of metallic path between them (snakes, etc) the bonding really ought to be their as well.

NEC requires multiple services in the same building to be bonded grounds
Title: Re: What do you want in a genny?
Post by: jasonfinnigan on October 02, 2014, 09:43:31 pm
That's a trailer that is designed and sold by MQ to do exactly that. Is the 14ga modification that you cite something that Honda designed and sells, or is it a proprietary custom thing? I think purpose designed and built by the manufacturer is a different ballpark then a custom build thing. One would give you the protection of MQ/Honda in case of a failure, the other... wouldn't...

-Ray

exactly
Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 02, 2014, 10:01:52 pm
My MQ Ultra Silent 60 generator came mounted on a trailer built by Mighty Mover - it was not designed and built by the manufacturer.  The fuel pump modification we do uses Honda original parts in a Honda designed fuel system. It gives you just as much protection as a MQ plumbed to a third party trailer.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
And that is not what I am talking about... I am referring to the trailers (http://www.multiquip.com/multiquip/pdfs/TRLR70XF_rev_4_DataId_259818_Version_1.pdf) that are actually built by their respective manufacturers. It's cool that you bought your gennie from someone who installed it onto their own trailer, but I submit that you would have the same liability concerns as your custom built Honda fuel cell setup, as opposed to something that Honda designs and certifies as being safe.

Lots of people fly line arrays from forks and such- and they always do that at their own risk, except for one company I know, who had JBL inspect their suspension-from-forks-of-a-grade.all setup -- from what I was told, it's the only setup of that nature that JBL actually came, inspected, and said "yes, this is safe."




edit cos i fubar'd up the url
Title: Re: What do you want in a genny?
Post by: Guy Holt on October 02, 2014, 10:35:21 pm
It's cool that you bought your gennie from someone who installed it onto their own trailer, but I submit that you would have the same liability concerns as your custom built Honda fuel cell setup, as opposed to something that Honda designs and certifies as being safe.

I'll say it again, the fuel pump modification we do uses Honda original parts in a Honda designed fuel system that Honda certifies to be safe. And, my MQ Ultra Silent 60 generator came direct from MQ mounted on a trailer built by Mighty Mover. 

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Title: Re: What do you want in a genny?
Post by: Ray Aberle on October 02, 2014, 10:54:11 pm
I'll say it again, the fuel pump modification we do uses Honda original parts in a Honda designed fuel system that Honda certifies to be safe. And, my MQ Ultra Silent 60 generator came direct from MQ mounted on a trailer built by Mighty Mover. 

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
Ah ok, well that's different then. You said before that it wasn't something done by MQ, and now it is- sorry to try and call you out, but I was going with what you said, and I guess that wasn't what you really meant. :) Like the Honda thing-- how you phrased it, "the modification WE do" would make someone think that it's NOT something done by Honda. I don't want to be an ass, but details matter my friend. Going back through the whole thread, (which I do, just to make sure I am not missing something) -- everything from when you first mentioned the fuel caddy for a Honda made it sound like an unauthorized modification that your company decided to make, which is why you were questioned about potential liability, and implying that the MQ trailers were also an unauthorized modification of the same inclination.

Again, sorry to try and call you out on anything, but I was going by what was being said at the time, and it is now apparent that I did not have a full grasp as to what you were trying to say.

-Ray
Title: Re: What do you want in a genny?
Post by: Frank DeWitt on October 03, 2014, 01:00:05 pm
Mods and liability.
Do we KNOW that modifying a generator increases or decreases the liability?  if so, what mods? 
Can you clean it?
Can you bolt it to a trailer?
Can you refuel it?
Can you ground it?
Can you connect the ground to the neutral?
Can you paint it?


I know that I have often observed insurance and liability used as a stick  (Customers are not allowed in the shop for insurance liability reasons.) but I have never talked to a insurance company or lawyer who could really tell me. 

For that matter, has anyone ever got a straight answer from a insurance company?

I write this as a guy who has restored and modified cars. OK I have modified every car I have ever owned.  Also a guy who designed and built the house I live in, and has helped other volunteers do a lot of building, rebuilding, and modification at church.

My mower is extensively modified (Tires, hitch, oil cooler, and more)  I think my 53 Farmall is stock, no, I added fenders and changed the lights, and I modified my hammer.
Title: Re: What do you want in a genny?
Post by: Jonathan Johnson on October 03, 2014, 02:51:16 pm
Mods and liability.

OK, so I buy an extension cord made by Woods. The ground pin breaks off, so I dutifully replace the male plug with a replacement plug made by Cooper Electric and listed for the purpose. I follow all the instructions included with the replacement plug precisely.

Somewhere down the road, there is a failure of the extension cord, and it's determined that the failure has something to do with the termination at the male end of the cord. Who is liable? Cooper may disclaim liability asserting that the failure was with the cord, not the plug. Woods may disclaim liability because the cordset was modified without their express permission.

If it's me, should I never be allowed to repair cords? Am I required to dispose of them? Or must I have a licensed electrician or UL repair shop perform the repair, at a cost greater than simply replacing the cord?

There's gotta be some "common sense" ground here.
Title: Re: What do you want in a genny?
Post by: Frank DeWitt on October 03, 2014, 03:08:07 pm
 Mike Sokol has developed a excellent talk on grounding and the dangers of reverse polarity bootleg ground.  He has developed some well researched and well made show and tell demo equipment for his teaching.   I would like to invite him to bring his equipment and his talk to the church I attend and teach us.  I would also like to invite the local fire marshal to attend.  Will our church lose it's insurance?  Will we be able to get new insurance ever again.

At some point the don't mod it because it will cause a liability / insurance problem is real.  At some other point it is something to consider and something we don't know the answer to.  At another point it is a meaningless weapon to wave around and paralyze people.

I personally have seen a insurance company refuse to even quote a price for liability on a new product only because it was new so they had no history to gauge risk.
I have also seen them pay a clam on a car damaged on a race track while the owner was taking a high speed driving coarse.  They said the (Modified) car was licensed and insured and being used in a manor that was legal so it was covered.   In other words I can't tell.
Title: Re: What do you want in a genny?
Post by: Craig Hauber on October 03, 2014, 11:17:55 pm
From my IA Grounding/Bonding Workshop:

(http://www.screenlightandgrip.com/images/generators/ProSound_PP_Image_Bonding_Separately_Derived-Systems.jpg)

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com

Are you tying the neutrals together in that diagram or just the ground wires? (small screen and eyes not too good anymore)
I guess that's a moot issue if G-N is connected in the generators
On that note, Do you G-N connect at all generators or only at one?  how about ground rods -at each one or centrally?
Title: Re: What do you want in a genny?
Post by: Stephen Swaffer on October 04, 2014, 11:49:22 am
Each genny needs to be G-N bonded to provide a path for fault current generated by that genny to return to the neutral of that genny so that OCPD (breakers) will trip when a fault occurs.

Then their needs to be a grounding electrode system (ground rods) for the installation, then anything that can possibly become energized-stages, lighting truss, gear racks all needs to be bonded to that same system.  Bonding simply being defined as "an intentional electrical connection".  Bonding conductors should be sized according to the main breakers in the largest genny used.  If, for example" an extension cord plugged into any genny gets nicked and shorts to any metal part of your install, the electricity needs a good metallic path back to the neutral so that a breaker trips.  Also, the human body has a higher resistance than a good metallic bond-so the current will not flow though a person causing harm.

In permanent systems, each structure and service would have its own grounding electrode or set of ground rods-I am not sure in a temporary install if that would really be necessary-but others might disagree?  IMO bonding would be more important.