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[StJohn Gill II]

Hi guys,

Quick question, due to temporary stupidity, can someone please tell me what is the wattage and therefore amperage of 2x 110v 1000W Par 64's in series. (For you 120v land guys, we use adapters in 250v lands to put two of your crazy lamps in series.... ).

I can't get straight in my brain whether it becomes 1000W at 250v  (4A) or does something else.

Thanks a bunch.  

[Phil LaDue]

Check this out.
http://www.opamplabs.com/eirp.htm

[Brian Ship]

About 16.66 amps.

On the other hand, why not use 230 or 240v PAR lamps?  Realizing our 1K lamps are popular down under but it's for all intensive purposes the same lamp / different and proper voltage in using the proper lamp such as the EXC thru EXG series / CP-95, CP-60, CP-61, CP-62.

Just curious why you don't use your own voltage rated lamps?

[Silas Pradetto]

Brian Ship wrote on Sat, 03 January 2009 00:55

About 16.66 amps. On the other hand, why not use 230 or 240v PAR lamps?  Realizing our 1K lamps are popular down under but it's for all intensive purposes the same lamp / different and proper voltage in using the proper lamp such as the EXC thru EXG series / CP-95, CP-60, CP-61, CP-62. Just curious why you don't use your own voltage rated lamps?

I somehow think that's wrong...

You'd be drawing 16.6 amps through a SINGLE unit on 240 volts, which is why it would explode...but a series circuit is a voltage divider, so they are seeing 120 volts each, so they are still 1000 watts @ 8.3 amps each, and the total current in the circuit is sill 8.3 amps.

P=IV
2000=8.3*240

So, we have 2000 watts total, 240 volts total, and 8.3 amps total.

[Rob Timmerman]

A "1000W at 120V" PAR lamp can be approximated quite well as a 14.4 ohm resistor.  So it dissipates 1000W when driven at 120V and draws 8.3 amps.  If you put 240V into this same lamp, it will draw 16.6 amps, and dissipate 4000W.  If you put 2 lamps in series, you now have the equivalent of a 28.8 ohm resistor, which will draw 8.3 amps and dissipate 2000W.

[StJohn Gill II]

Thanks a heap guys, I figured Robs solution was the way to go but wanted to double check.

@Brian Ship. According to specification, 110v lamps have a lamp life about 10 times that of a CP62 (3000hrs versus 300hrs). They also have a slightly lower colour temp, but not enough to really bother unless you are in TV perhaps? (2950 vs 3200)

Have a great week!!!

[Brian Ship]

noted on the amperage.

Most ANSI lamps are 800 hrs, the 4,000 hour long life versions also give up a lot of intensity to get there.   But on the other hand, 4,000 verses 300 hours is a good point.

[Tom Williams]

Hey john, what do you use to adapt the lamps, like a box splitter 1 in 2 out doover or y-split? And do you use round earth pins?

Oh and just to be a smart arse    it's getting towards 230V nowadays, then again it got de-regulated so they can produce 250V on saturday and 230 on sunday if they want ha ha.