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Author Topic: Autoformers, anyone?  (Read 1647 times)

Jonathan Johnson

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Re: Autoformers, anyone?
« Reply #10 on: October 17, 2017, 02:27:43 pm »

There's no need for an "autoformer" to monitor the current. All it really needs to do is monitor the voltage and switch to a different tap as changes in current load cause different degrees of voltage drop.

This sounds to me like a marketing schmuck asked an engineer what it does, and with absolutely no understanding of electricity, tried to translate what the engineer said in plain English. Epic fail.

* * * * *

My uncle was an autofarmer. At least that's my guess, based on the countless hulks rusting out behind his barn.

He would have told you every one of them "has a good motor" -- probably because every one ran when he parked it there, anywhere from 60 years ago to within a couple years of his death a few years ago.

Shortly before he died, he managed to sell some of them to people interested in restoring them as classics. Probably made more money selling the hulk than he ever paid for the car.

(Sorry for the diversion. It's just the word "autoformer" made me think of "autofarmer" and that made me think of my uncle.)
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Marc Sibilia

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Re: Autoformers, anyone?
« Reply #11 on: October 17, 2017, 08:32:39 pm »

Interesting. So my understanding is that the reverse EMF caused by the self-generator action of the AC/DC (or DC) motor is what limits the winding current as the rotational speed reaches some maximum design limit. But I think you're saying that pure AC motors actually change their impedance based on the slip angle speed of the rotor as compared to the rotating magnetic field. So if you added another motor to spin the first motor in phase with the line frequency, then the winding impedance would increase, and thus draw significantly less current. Am I thinking about this correctly?

That is correct. You got it.

And the reason that universal motors don't like low voltage is that they are often used on devices like saws, drills and routers where the load (the work to be done by the motor) doesn't change with the voltage.  Who slows down their cut when the drill isn't running as fast? Most people will just push harder to try to make the same cut rate.  If a universal motor were running a fan, the load would go down with the voltage and the speed of the motor, and the motor would be perfectly happy (and cooler) running slower.
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Mike Sokol

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Re: Autoformers, anyone?
« Reply #12 on: October 17, 2017, 08:38:21 pm »

This sounds to me like a marketing schmuck asked an engineer what it does, and with absolutely no understanding of electricity, tried to translate what the engineer said in plain English. Epic fail.

Yup, I talked to the owner of the Autoformer company today, and that's exactly what happened. I told him it had to have been written by someone either misinformed or lying, and he admitted he had never read that page on his own website and assumed that the marketing guy wrote something appropriate. Since I'm doing a story about this technology for RVtravel.com next month, I gave him the option of rewriting his website to correct the inaccuracies, or I would list the errors line-by-line and detail why each statement was wrong. I don't think he's a bad guy, but he wasn't paying attention to his own marketing hype.

Stephen Swaffer

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Re: Autoformers, anyone?
« Reply #13 on: October 17, 2017, 08:53:52 pm »

Unfortunately, inaccurate marketing hype will drive some potential customers away-the ones that understand what is going on-because some will assume they are just selling a gimmick trying to make a quick buck.  Others will expect the product to deliver performance it simply cannot leading to bad word of mouth.

Sounds like a useful product in some situations-though certainly not a silver bullet for every situation.  Low voltage caused by long conductors that were not upsized properly is a relatively benign situation that this device would work well to correct.  Low voltage caused by bad connections caused by age or whatever, not so much.
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Steve Swaffer

John Roberts {JR}

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Re: Autoformers, anyone?
« Reply #14 on: October 18, 2017, 09:22:41 am »

Unfortunately, inaccurate marketing hype will drive some potential customers away-the ones that understand what is going on-because some will assume they are just selling a gimmick trying to make a quick buck.  Others will expect the product to deliver performance it simply cannot leading to bad word of mouth.
In my experience the fraction of customers who understand even basic technology was minimal... For most of my career I have had the luxury of writing (or approving) my marketing copy. That did not stop a few over-enthusiastic selling machines from going off the reservation. I remember one (west coast) AES show where I had to literally follow around a new sales manager and correct his spiel... He memorized the right buzz words but had no clue what they meant.
Quote
Sounds like a useful product in some situations-though certainly not a silver bullet for every situation.  Low voltage caused by long conductors that were not upsized properly is a relatively benign situation that this device would work well to correct.  Low voltage caused by bad connections caused by age or whatever, not so much.
Bump windings are even used by utilities so they have their place.

JR

@Mike maybe offer the company your suggestions for a more accurate description, just telling him it's wrong doesn't fix it. I would be (I am) surprised he was so receptive, I probably wouldn't be, but i wouldn't be so wrong. 
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Mike Sokol

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Re: Autoformers, anyone?
« Reply #15 on: October 18, 2017, 06:54:00 pm »

@Mike maybe offer the company your suggestions for a more accurate description, just telling him it's wrong doesn't fix it. I would be (I am) surprised he was so receptive, I probably wouldn't be, but i wouldn't be so wrong.

JR, yes I did offer him a few suggestions, and he asked if he could run the changes by me before it goes live. I think he was so receptive because he's an engineer who bought the company, but didn't read the marketing bling and just assumed it was right. He seemed totally embarrassed as he kept reading the copy over and over to me on the phone, saying it made no sense and was probably wrong.

Also don't discount the fact that my RVtravel.com articles get emailed to 50,000 readers every Saturday. This is the primary product of a small company, so any bad press could really hurt them. I don't go bashing products unless they really deserve it. In the right application, I think the AutoFormer can do a good job. But it has obvious limitations and can't perform miracles. 

Tim McCulloch

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Re: Autoformers, anyone?
« Reply #16 on: October 18, 2017, 07:28:24 pm »

JR, yes I did offer him a few suggestions, and he asked if he could run the changes by me before it goes live. I think he was so receptive because he's an engineer who bought the company, but didn't read the marketing bling and just assumed it was right. He seemed totally embarrassed as he kept reading the copy over and over to me on the phone, saying it made no sense and was probably wrong.

Also don't discount the fact that my RVtravel.com articles get emailed to 50,000 readers every Saturday. This is the primary product of a small company, so any bad press could really hurt them. I don't go bashing products unless they really deserve it. In the right application, I think the AutoFormer can do a good job. But it has obvious limitations and can't perform miracles.

Q.  Do I *need* an autoformer?

A.  How sketchy is the power at that new campground you've never stayed at?

Q.  What will an autoformer do for me?

A.  It will make voltage-sensitive appliances and electronics work like they're supposed to, avoiding potentially shortening of service life.  It might also uncurve your spine, unwarp your mind and win the war for the Allies...
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Mike Sokol

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Re: Autoformers, anyone?
« Reply #17 on: October 18, 2017, 11:21:14 pm »

Q.  Do I *need* an autoformer?

Here's one thing that it will really do. Many RVers have some sort of "smart" surge protector in their shore power  line that monitors the incoming voltage and will open up a contactor relay if it goes below some threshold of around 102 volts or so. In order to save the air conditioner compressor from a hot-start which draws a huge amount of current with a locked rotor, there will be a significant delay of up to 2 or 3 minutes before turning the power back on to the RV. So in a campground with low voltage and a lot of RVs using air conditioners, these smart surge protectors can cycle the power on and off to the RV several times an hour, which doesn't make the owner of a $250,000 RV or $500,000 coach very happy. By boosting the low voltage from the pedestal by 10% with an "Autoformer" those power outages in the RV will be avoided.

With the exception of the microwave, and compressor/fan motor on the HVAC unit, practically everything else in a modern RV has some sort of universal switching power supply, rated for 90 to 250 volts.

Steve M Smith

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Re: Autoformers, anyone?
« Reply #18 on: October 19, 2017, 06:00:56 am »

Is autoformer a real word in the US?


Steve.
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Mike Sokol

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Re: Autoformers, anyone?
« Reply #19 on: October 19, 2017, 07:05:10 am »

Is autoformer a real word in the US?

Steve.

Nope... It's a registered trademark.
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