Member postings for john lancaster

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14/04/2016 19:08:49

Hi,

Going back to my youth and acquired a a broken Chinese Mini Lathe, unfortunately it had blown the fuse and on replacement it remained dead.

Using this site I have completed some diagnostics and repair, but would really appreciate the help of those more experienced.

What I have done so far:-

1. Removed 250W Brushed Motor ZYT-250 and connected to a 12v supply. Runs not that smoothly but draws 850mA, Stall current 2.2A at 12v. At 36v it draws 2A. Seems excessive.

2. Opened motor tested commutator at 180 degree and adjacent windings for resistance. Seemed OK. Brushes seemed OK. Nevertheless suspect motor.

3. Removed controller board SMT FC250J. Tested FETs as described on this site, one was shot. Replaced both FETs and tested into a 60W bulb load. Now works but hums with a 'inverterish' noise, if you know what I mean! Have ordered the electrolytic caps as described by others on this site.

4. Have not connected the motor to the controller as I suspect the motor could cause damage again. New motor is £90!

Any thoughts would be appreciated.

many thanks

John

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