1968 Modular 10ee missing a transformer ?
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  1. #1
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    Default 1968 Modular 10ee missing a transformer ?

    1968 10ee Modular purchased condition unknown. While checking a capacitor mentioned in another post as often a problem source, the outline of a transformer base appears, but no obvious connections for one. This is accessed from the rear of the lathe, in the box with other transformers and a terminal strip. No power applied yet, still gathering other missing parts. Monarch records show machine as 220 volt as delivered, but currently connection is 480 volt.

    Looking for info on what transformer may mount here....picture below.

    Side note, additional picture of external transformer, guessing 480 to 220/240 ?

    eb1f6f37-d5b9-4346-a50f-34d1c455a328.jpgc30e2e83-ac9f-4378-a384-d5c1b347d20a.jpg0
    Attached Thumbnails Attached Thumbnails 0cd57710-a702-43ae-b7b2-a22391aa1681.jpg  

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    Using the circuit diagram identify the transformers you have and then the last one on the circuit diagram is the one you are missing.

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    The transfomer identified on the schematic as "T4" is normally the one that sits in that blank spot. Since someone appears to have strapped in the capacitor that normally connects to T4, and there are also wires connected to circuits 31 and 32 on the top side of your terminal block, it would appear that someone has installed a replacement or alternative for T4 elsewhere in the transformer compartment.

    Here is a bit more detail that might help:


    T4 is specially wound with what I would call a pony winding which connects to the 1uf capacitor shown in your photo. The only function of the combination is to deliver a 270 vac squarish waveform (the pony winding and capacitor do this by introducing a harmonic into what would normally be a pure sine wave transformer output) to the voltage reference circuit of the control. The voltage reference circuit then rectifies this squarish waveform to produce a rather poor DC reference. Just about any dc reference will work as long as it is in the 270 - 300 volt range. Based on your pictures it looks to me as if someone has provided an alternative solution for T4. You can see what they did by following the black wires that come off the top side of terminal block positions 31 and 32.

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    Quote Originally Posted by Timothy Jones View Post
    The transfomer identified on the schematic as "T4" is normally the one that sits in that blank spot. Since someone appears to have strapped in the capacitor that normally connects to T4, and there are also wires connected to circuits 31 and 32 on the top side of your terminal block, it would appear that someone has installed a replacement or alternative for T4 elsewhere in the transformer compartment.

    Here is a bit more detail that might help:


    T4 is specially wound with what I would call a pony winding which connects to the 1uf capacitor shown in your photo. The only function of the combination is to deliver a 270 vac squarish waveform (the pony winding and capacitor do this by introducing a harmonic into what would normally be a pure sine wave transformer output) to the voltage reference circuit of the control. The voltage reference circuit then rectifies this squarish waveform to produce a rather poor DC reference. Just about any dc reference will work as long as it is in the 270 - 300 volt range. Based on your pictures it looks to me as if someone has provided an alternative solution for T4. You can see what they did by following the black wires that come off the top side of terminal block positions 31 and 32.
    Thank you for the reply and especially the explanation. Your suspecting a non standard replacement of T4 is valid. This one is larger than the original, includes a box like structure at one end holding the leads and a fuse holder. The installed fuse is 1/2 amp, not 5 amp shown on the schematic I have. I am wondering if it is a correct / equivalent replacement. Will see when have power to the lathe and can measure voltages. It is below the terminal strip and in between T5 and T3, and that is what the capacitor is zip tied to in the picture.


    Thanks again,

    Bob


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