timer question, can I use a 240v timer with 120v enlarger?
This seems a bit stupid but I'm very confused about how to choose enlarger timer, as I have only used Ilford 500 system before and it can be switched between 110v-240v, and its timer is connected directly to the transformer.
But currently I'm building my LPL 7452 system. I plan to use an Analyser Pro with it. The question is, my lpl 7452 is 120v, while here the wall plug is 240v; should I use a 120v analyser pro (which is a timer/densitometer) with it, or a 220v version?
I'm very confused here, please help!
Last edited by slight; 03-18-2013 at 06:07 AM. Click to view previous post history.
You cannot plug a 120V appliance into 240V. It will burn very quickly.
Could you change the lamp to a 240V version?
Originally Posted by Jesper
Yes I am aware that I must use a transformer to use the LPL 7452 when the wall plug is 220v.
BUT, my questions is, can I plug a 240v analyser pro timer in this 120v lpl 7452 enlarger??
You will need a transformer to convert the 240v mains to 120v for your enlarger. It would be best to use a 120v Analyser Pro, so you'd plug the transformer into the 240v mains, plug the Analyser into the 120v from the transformer, and plug your enlarger into the Analyser's Enlarger socket. Alternatively (and this would be a better solution) you could find a 240v version of the LPL power supply. The Analyser is simply a mains switch so no, you cannot plug your 120v enlarger into a 240v Analyser.
Is your enlarger a colour or VC head? They use (I think) a 24v lamp so you'll already have a transformer to convert the 120v to 24v - the best solution is to replace that with a 240v-24v transformer.
Thanks Richard, that is very helpful!
But can I actually replace the transformer without burning anything? Because, the lamp itself is a 84v 250w lamp, not 24v. When I replace the 120v power unit into a 220v one, do I need to replace the 84v lamp into a 24v one?
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I found the following explanations on khphto's ebay store.
"250W/24V Quartz-Halogen replacement lamp for LPL model 7452 and 7452L 4x5 Dichroic Colour, VCCE Variable Contrast, and B&W Diffusion enlargers with 24V power supplies. The 24V power supplies are typically supplied with these enlargers in areas with 220V or 240V electrical service. "
Does it mean I can switch the 82v lamp and 110v power unit into a 24v lamp and 220v power unit combo, without modifying anything?? What about the fan? The fan won't burn when the mains power jumped from 110v to 220v??
Yes, I had a quick look on the web and it seems it is an 84V (or 82V) lamp on the 120V transformer.
It MAY be as simple as just changing the bulb for a 24V one, but it is going to depend what the rest of the wiring is. 250W into 24V is >10A which is a lot more than 250W into 84V which is only 3A. 10A over wiring designed for 3A could get a little warm! It isn't a complex system - just a regulated transformer and a bulb, so provided that all parts match it should be easy to re-build to the new voltage. However, if you are unsure I would take the problem to an electrical engineer - perhaps an auto-electrician, or perhaps electrical engineering at the local college - anybody who knows how to safely build electrical systems.
However I would probably consider plan A and get a 240v-120v converter transformer - easily available- big/robust ones used on building sites. As Richard says, get a 120V analyser and plug your 120V enlarger straight into it. May well be the neatest/easiest solution rather than messing around with the potential issues of converting a 120V enlarger (if you are not quite sure what you are doing).
EDIT just seen your remark re the fan - this could also be designed for particular voltage. Suggest external 240v - 120V transformer with a 120V analyser is definitely the simplest route
I got it, if I want to modify my 7452 into 220v version, I need to replace the WHOLE lamp house (which includes the fan), the lamp, AND the power unit.
This is really a pain. I will simply buy a 120v analyser pro, and a 220v - 120v transformer.
But this leads to another question, will the 220v-110v transformer affect the enlarger's light output stability???
Thanks Mr. Rusty, just saw your post. Yes indeed I will now try to finder a decent transformer.
One thing that concerns me is whether this will affect the current quality and in the end affect the enlarger's light output stability. Is it worthwhile to get a stabiliser along with the transformer?
No. The Enlarger still has it's stabilizer. The step-down transformer just works to convert your power supply as if it was a 120V supply. Depending on which transformer you get you may need to wire up a lead to convert the socket on the transformer to the socket on the analyser. The chain of devices is:-
enlarger's light output stability???
240v mains => stepdown transformer => 120V mains => 120v analyser => 120v enlarger transformer (with its regulator) => enlarger/fan/bulb
Just one other thought. If you are going to use the analyser safelight output you will need a 120v bulb in the safelight as well.
If it were me I'd get a building site stepdown. Very easy to find, high rating so won't overheat. Even the smallest are probably 1kW. like this:-
or you could get something like this:-
I'd go for 1kW minimum, even though you are only drawing 250-300W.
Last edited by mr rusty; 03-18-2013 at 10:43 AM. Click to view previous post history.