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#165369 06/26/07 02:23 PM
Joined: Feb 2004
Posts: 75
I was wondering if anyone has heard the rumor that once you use a multivolt ballast on one voltage it "locks on" to that voltage and can't be used on any other voltages. It has become a controversial subject here at the shop. The main reason for it is to temp the lights in on 120V while working and then go back to the 277V for the permanent installation. I was just wondering what other people have heard. I figure if that isn't ok, then there would be a large warning sticker on the ballast saying so.

Joined: Nov 2006
Posts: 348
ITO Offline
Never heard that before and I used lots of salvaged mvolt ballasts.

101° Rx = + /_\
Joined: Sep 2006
Posts: 58
I don't know if it affects ballasts, but I saw in the instructions for a multi-volt photocell, it said that when used on the higher voltage you couldn't go back to 120.

Why not try one and see what happens, Let us know, as I'm curuious too.

Joined: Jun 2004
Posts: 56
I too have never heard of anything like this, nor can I think of any mechanism that could be at work to make it so. I have used many ballasts recovered from old streetlights with multivolt tappings, at different tappings to the original configuration, and I can't say that I have ever seen any fail from this.
I would also be very interested to find out more about this.

Mark aka Paulus
Joined: Sep 2006
Posts: 58
I could be wrong, but I think the OP is discussing multi-volt electronic ballasts not the multi-tap magnetic ones.

Joined: Jan 2005
Posts: 61
One method used to keep from going back to lower voltages uses semconductor diodes as part of the circuit. Once the PIV (peak inverse voltage) goes above the level for the lower voltage,the diode opens. I haven't seen one of those in quite a while. I heard that manufacturers were no longer using that circuit so that ballasts COULD be recycled rather than ending up as land fill.

Joined: Apr 2002
Posts: 7,323
Likes: 7
Anybody think of asking the mfg??

Joined: Sep 2005
Posts: 421
you're fired..:)

can't have folks going around thinking

Joined: Sep 2006
Posts: 58
You shouldn't ask the manufacturer. He will give you the answer and we won't get to gum it to death.

Joined: Jan 2001
Posts: 1,044
Tom Offline
Well, I actually did call the MFG one time and the particular catalog # I was dealing with did not have a memory and I could use 120 or 277 and then switch to the other voltage.

Few things are harder to put up with than the annoyance of a good example.
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