Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,933   Posts: 1,585,552   Online: 825
      
Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16
  1. #11
    ic-racer's Avatar
    Join Date
    Feb 2007
    Location
    Midwest USA
    Shooter
    Multi Format
    Posts
    6,394
    Transporting a DeVere 810 to Chicago To Bangkok. That is quite a move. Unless you have the schematic for the power supply and timer, I'd check with Oddesy sales about the best way to deal with the voltage/Hz change.

    I would have thought that a 'digital' timer would have a crystal in it, but the Durst L1840 keys off the Hz of the power supply. In fact it sends the 60Hz pulse up the edgemost wire of the ribbon cable, which can get damaged if the enlarger runs over the cable (ask me how I know....).

  2. #12
    EricNelson's Avatar
    Join Date
    Jan 2005
    Shooter
    Medium Format
    Posts
    14
    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


    Quote Originally Posted by polyglot View Post
    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.

  3. #13

    Join Date
    Nov 2002
    Location
    Melbourne, Australia
    Shooter
    Medium Format
    Posts
    1,012
    Quote Originally Posted by EricNelson View Post
    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
    The transformer I use is a portable one like this:

    http://australia.rs-online.com/web/p...rmers/2604294/

    I had to use some European plugs for some of my setup, but a different plug/socket for each voltage makes sense. I made a distribution board with some US type outlets and some local 240V outlets. The output of the transformer is centre-tapped to earth which is a safe design.

    polyglot has dealt with the issues of total power capacity and frequency. Most devices will not care if the freq is 60 or 50, but mains freq is used for speed or sync control in some, such as old TV sets, certain motors that are locked in to the freq, and, as a previous poster has suggested, the enlarger might need the freq for some electronics. You don't want to take any chances with such a piece of equipment.

  4. #14

    Join Date
    Nov 2002
    Location
    Melbourne, Australia
    Shooter
    Medium Format
    Posts
    1,012
    Quote Originally Posted by EricNelson View Post
    .... my Aristo cold light on my D5......

    Eric
    I know from experience that you'll have no trouble with the Aristo unit using a good transformer.

  5. #15
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,341
    Images
    12
    Quote Originally Posted by EricNelson View Post
    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
    Yes, a 2kW transformer for the press will be perfect. Since your enlarger is so huge (I didn't see the 8x10 bit), it's possible that it draws full 1200W. Adding up the bulb ratings, adding about 50W for the fans and then multiplying by 1.15 (for the transformer inefficiency, if it has one) will get you the total power consumption of the enlarger. If the enlarger has no transformer, i.e. the bulbs run directly off 110V then you don't need to have a 2x over-rated stepdown transformer for it, but it won't hurt to give it some breathing room of 1.5x or so.

    An oversized stepdown transformer will run cooler and more efficiently and there's very little difference in price between 1kVA ($60) and 2kVA ($70) but 3kVA starts to get expensive ($130), so it's a good idea to split your loads into groups of 1000-1500W and run each group off 2kVA transformers.

    Your surge protector (if any) should be rated for the voltage it's being used on. If you have a 110V surge protector, you can use it downstream of a stepdown transformer and if you want anything else to run on 220V with a surge protector, you'll want to buy that protector locally. If you plug a 110V surge protector into 220V, you'll let the magic smoke out. I would recommend an UPS over a surge-protector any day because we get 5s dropouts here every couple months.

  6. #16
    EricNelson's Avatar
    Join Date
    Jan 2005
    Shooter
    Medium Format
    Posts
    14
    I'll give them a call, thanks ic-.
    e

Page 2 of 2 FirstFirst 12


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin