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.
Never heard that before and I used lots of salvaged mvolt ballasts.
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.
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.
I could be wrong, but I think the OP is discussing multi-volt electronic ballasts not the multi-tap magnetic ones.
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.
Anybody think of asking the mfg??
John
you're fired..:)
can't have folks going around thinking
You shouldn't ask the manufacturer. He will give you the answer and we won't get to gum it to death.
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.
I did email the manufacturer and just wrote me back. Here is what he had to say.
Thank you for contacting Universal Lighting Technologies.
Any Triad ballast containing ‘UNV’ as part of the catalog number continuously monitors the incoming line voltage and regulates for that incoming voltage in real time as long as the line voltage is between 108V minimum and 305V maximum, and source frequency is at 60- or 50-Hz. This comes in very handy on a commercial site where the temporary power is 120V prior to commissioning of the 3-phase 277/480V power.
If we can be of further assistance please don't hesitate to let us know.
It's reduced to an urban legend among electricians.
I have heard it many times.
It's out of date. New stuff is 'intelligent' and never stops looking at the line voltage.