View Full Version : Timer for Aristo coldlight

28-Jul-2016, 16:34
I just bought an Aristo cold light and will replace the tube with a V54 tube. I have a EPOI Printrol solid state timer, rated for 500 watts. Aristo says a 1200 watt inductive load rating is needed. Inductive load is not the same as the load from an incandescent bulb. Aristo has contractor that will marry the two. The question is--Does anyone have experience with this? Do I really need the contractor? Or not.

William Whitaker
28-Jul-2016, 16:53
Not a "contractor", it's actually called a "contactor" and is nothing more than a relay. It would be advisable to get one if you want to use that timer. Digital timers generally do not like inductive loads.

28-Jul-2016, 18:01
Darn autocorrect! I didn't catch it-thanks. Thanks for the info.

28-Jul-2016, 18:10
The EPOI 301 timer you have is also marketed under the Kearsarge brand name. I have the Kearsarge 301 which has a digital readout but is otherwise the same as the 301. In particular, it is a 500 watt unit as well. I have been using it with an Aristo cold light head for years without problem. I have the original Aristo bulb rather than the newer V54. Perhaps it has a more reactive load.

28-Jul-2016, 18:21
Probably don't need it... I have used standard timers with normal cold lights, and I haven't burned out a timer relay yet...

Having a good relay in your timer will probably not be damaged, but if the relay has pitted contacts or on the way out, the light might push it over the edge...

If you are not sure (and don't want to buy their relay), you can go to an electrical supply house and buy a 120V relay for not too much and an electrical box with an outlet and a power cord... You would wire the relay primary coil contacts with the 120VAC coming from the timer, and the lights leads go across the relay contacts and connects to another power outlet...

Steve K

28-Jul-2016, 20:46
Which Aristo head did you buy? 1200 watts seems awfully high. My D57 draws 90 watts if I recall correctly. It's probably a lot cheaper to get a new timer, if you try your existing timer and you fry it, you can certainly replace it for not much. L

30-Jul-2016, 14:44
Years ago I got bought a $12 relay from Granger and set it up so my digital timer trips the relay, which in turn is just a wall power switch to the cold light. Very easy and cheap compared to what they sell (or sold) for darkroom use. I figured it was a nice safety measure for anything I might want to plug in and time.

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