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- Jan 18, 2005
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I live in a 240volt area and my whole darkroom is 110volt because when I started, some gear, for example Zone VI, was only available in the US voltage. I use a good quality high capacity transformer. My new gear is 110volt as well, just to keep everything simple. Theoretically it could be considered safer in the event of a damaged wire etc, I suppose.
One thing to watch is the capacity of the transformer. Once, I had a spare 240v to 110v transformer that came with a Beseler enlarger. I lent it to a friend who had just come back to Australia from the US and she had some 110v Christmas tree lights. I didn't consider the current draw of the lights, and the transformer lasted only a couple of seconds.
first, you have ot be sure to use the step down transformer on any gear that does not auto switch. Putting 220 on something that is expcting 110 is likely to let out the magic smoke.
Close examination of gear originally made in places that use 220 volts may find that a technician can re-wire it to work on 220. Likewise, many units have in internal jumper for 50-60 Hz. Many european devices have a 110-220 switch, which is sometimes hidden in North America to avoid customers not aware of the issue fiddling with it.
Worry 1 is that a motor will often run hotter on 50Hz than on 60hz. If the motor was designed for 50-60Hz this will be taken care of, again you have mostly European designs in your list, so the designer may have actually built the unit for 110v 50Hz
Worry 2 is that timers often key off the power line. ie you would have to set the timer for 50 seconds to get a minute of timing.
Possibility for units gear is that there may be an interchangeable gear to deal with the frequency.
Final tip is to try and find a good electronic tech at your destination. some folks in less affluent countries will buy used gear and re-make it to work on the local supply. Transformers inside the unit can be remade for 220 rather than 110 for example.
Gear made in the last 5 years or so, is often equiped with a powersupply that does not care about the nature of the power, the ratings plate will say 100-240V.
The Jobo (agitation) motors are DC and run at about 20V depending on the speed setting. The speed is controlled from the front panel of the Jobo, which is responsible for regulating the DC supply to the motor, almost certainly by PWM. So your Jobo motor is not going to care what frequency your mains is at all and it won't overheat any more than usual, other than the fact that you're going to be in the Philippines.
The pump motor runs directly from the mains. It might slow down but likely there will be no difference at all.
About 75% of the 400W rating is the heating element, which really won't care about frequency.
Your timer says 10A on it because that's a standard relay rating (it's how much the timer can switch); it doesn't mean the enlarger pulls that much current at all. 10A at 110V is 1100W, which is a pretty big light bulb! Check the power rating on the bulb and use that as a guide.
Things like enlargers with transformers pull a huge inrush current (the "bong" the transformer makes when powered up), which will pull the line voltage right down. If you have a computer or something attached to the same transformer, it will possibly reboot when you turn the enlarger on. Otherwise, go ahead and connect as much as you want. Isolation transformers are rated in VA (volt-amps) not watts, though the vendors will generally just say watts when they mean the other. VA = W ONLY when the power-factor is 1, i.e. a purely resistive load, which most of the darkroom gear isn't. To be safe, you want a transformer with approx 2x the VA rating as the actual real watts you intend to draw from it.
For example:
- 500W enlarger
- 400W Jobo
- 10W safelights
- 5W timer
total = 915W. You therefore want a 2kVA ("2000W") stepdown transformer.
If you have a drymount press (probably 2kW), you'll want to have a separate transformer for that. It's a resistive load though, so you don't need a 2x larger transformer.
Make sure you buy an isolated transformer and not an autotransformer; the latter can be very dangerous to your equipment because their default (and common) failure mode is to let 240V straight through when the winding burns out. An isolating transformer will just stop working and transmit no power if it burns out.
While it is possible in principle for timers to time from the mains, it is much cheaper and simpler to use a crystal or RC timing circuit (e.g. 555) so I, as an electrical engineer, would be very surprised if an electronic (i.e. with LED digital displays and stuff) enlarger timer was mains-synced. Mains timing is generally only used for clocks where long-term to-the-second stability is desired. It's quite possible however that a semi-mechanical timer (one with a rotating knob that rattles its way around the dial) will change speed with the mains frequency since some of those run off a geared synchronous motor, for which the speed is locked to the mains frequency.
Thanks to everyone who has posted!
John, when you say high capacity, are you talking about a 3000 watt model? If my DeVere goes with me it will definitely need something powerful as it pulls 10 amps according to the back of the OEM timer that came with it. There's no mention of wattage.
Assuming the wattage of the converter isn't exceeded how many devices can you plug into your converters? I know they only have one outlet but I'm wondering if you've had success running more than one device via a power strip or surge protector or if that is not recommended.
Thanks
Eric
.... my Aristo cold light on my D5......
Eric
Thank you polyglot, you've answered my questions very well!
The 8x10 DeVere has 4 halogen bulbs plus 2 large fans so it may very well come close to that number of amps, but you're right and I'll check the bulbs to get a better read on that device.
You've saved me the trouble of opening up my CPP2 thank you!
Thank you as well for giving the method for determining the optimum type converter for my needs. I hadn't thought about my dry mount press so thanks for reminding me. It states, "115V AC only 13amps 1500W". So a 2K watt converter should work for that correct?
My computers either autoswitch or have a switch on the back. For anything like that, (plugged directly into 220V outlets) should I get a surge protector there that is for 220V or will any type work?
Appreciate everyone's answers as now there's a lot less stuff for me to worry about. Just the expense and logistics of getting it all there....to Bangkok.
Maybe I'll get to the Philippines some day.
Eric
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