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  1. #1
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    Red face Noobie ?? on Modular EE

    I'm not a noobie so I feel a little silly asking this one.

    I am not to familiar with Modulars and I am wondering how to tell what voltage the machine is set up for so I don't let any smoke out.

    I just picked up a nice '61 and it came from a source that didn't know what voltage it ran on and I'm just being careful.

    I know what to look for on MG's but not on these new fangled ones with tubes and such.

    Thanks in advance. Doug

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    Doug, The only way that I can tell is to have the electrical print and examine the transformers wiring placements.
    There is a shunt wire that has specified length also.

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    Good evening Donie and thanks for writing back. If I send you a picture can you identify the transformers that I need to look at?

    I know there are two with the C16's in the headstock cabinet, is it those or are there others behind the big front door?

    Regards, Doug

    PS, how common was it at that time to have the big quill tailstock with a #2 MT socket?

    I remember a guy picking one up like that here last year but I can't find that thread to look it over.

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    A Modular has two filament transformers, one for each C16J.

    The voltage should be marked on the transformers: 200, 208, 216, 224 and 232 for the 230 volt version, 400, 416, 432, 448 and 464 for the 460 volt version.

    Those transformers are mounted right below the C16Js.

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    Thank you kindly Peter, I will take a look tomorrow. We run a little high on our 230 and 460 in my neighborhood would it be advisable to adjust the taps if they are way off?

    I sure am glad you guys are out there to help.

    Good night, Doug

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    Doug, there is the big transformer behind the rear door.
    The large diameter quill tailstock at some point in time replaced the smaller one.

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    "Doug, there is the big transformer behind the rear door."

    That one is 230/460 volt.

    Also, whenever the voltage is changed, the two shunts to the current transformers, part of the load regulation circuit, must also be changed.

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    Default Modular Voltage setting

    Good morning and thanks again. I'm going over to peek inside shortly.

    I don't plan to change the voltage as I have the luxury of hi and lo voltage to work with but I am going to look into all of the items that Donie and Peter have mentioned to gain any knowledge I can.

    Thanks again, Doug

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    Doug

    Sometimes there is a voltage tag posted on the machine, not to say someone hasn't changed the voltage but not the tag.

    Hal

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    I think the best way to really tell is to look at the wiring on the REALLY big transformer in the transformer case (T5) (under the coolant sump, access from the back of the lathe). If the primary windings are in series, its wired for 440V (Line in on X1 and X4 , X2 and X3 wired together) and if in parallel (X1&X3 together on one side of the line along with X2&X4 on the other side of the line) then its 220V. You can check this on the wiring panel inside the back of the lathe, you don't have to pull out the transformer box, just remove the cover. It seems that most of the modulars have 440V filament transformers. You can run these on a 2:1 step-up transformer (at least 500 VA or more is OK), rewire the primary windings on the big transformer for 220V and then you still have to rewire the primary windings in the T3 transformer for parallel operation too (220 V to X1&X3 on one side, X2&X4 on the other side of the line). If you then replace the shunt wires on the current sense transformers (T1 and T2) you are ready to go. You may very well have to fine tune the filament transformers for the C16J's for 2.5 V on the filament when you're done.
    I think thats everything required to convert from 440 to 220.
    Cheers,
    Steve

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    A conversion from 440 to 220 also requires changes to the control circuit. If it has ELSR, the change is to rewire the control transformer (440V-110V) to be (220V-110V), assuming it is dual voltage (or replace it if it is not). If it doesn't have ELSR, it may require replacing the coil in the main contactor with a 220V coil, since non-ELSR machines generally use line voltage in the control circuit. And if the contactor coil gets changed, the heater coils need to be replaced with units that handle twice the amperage...

    -Dave

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    Damn, I knew I would forget something....Didn't know that the ELSR had a rewire associated with it. As far as the contactors go, at least on mine, I never got around to replacing the heaters or the contactor coil and it seems to be just fine so far (knock on wood). It will drop out under a really heavy cut, but I don't do that too often so it hasn't been as issue so far.
    Steve

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    Gentlemen, many thanks to all and I am glad to say that after reviewing the transformer connections and ascertaining (big word, eh) that the machine was in fact wired for 220 volts I plugged it in waited a few minutes for things to warm up and when I hit the go button I was rewarded with that delightful blue glow one can only see from two happy thyratrons.

    The machine cycled flawlessly and all is well.

    As someone here mentioned not to long ago, this has to be the best forum going as far as we can tell and I thank one and all again for the support

    Regards, Doug

    PS, now if I could just get the WIAD to do that I'd be in seventh heaven


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