The Craftmans Shop > New from Old

Yet another Beaver resurection (TC20F)

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philf:

--- Quote from: awemawson on March 06, 2019, 03:46:44 PM ---Instantaneous starting current on mine, which probably has a similar sized spindle motor, is over 100 amps. Needs a type C at least, but preferably a type D breaker.

(My spindle motor is a 27.5 kW Mawdsley DC motor with an appropriately large KTK-Mentor drive )

--- End quote ---

Andrew,

Doesn't the drive have adjustable ramp times? 100A just to start seems almost unbelievable. If that's the best it can do then I can only think it's a crap design!

Phil.

awemawson:
Phil, I went back and re-read my notes to check - actually the figure I'd remembered was the DC to the motor spindle, and was 109 amps. The inrush mains current was 90.5 amps

JeffK:
I spent a bit of time this afternoon prodding and poking to try to find out what was causing the EMG. Turns out thermal overload switch 2 had tripped. I reset and tried again but same thing (several times). They say something about doing the same thing over and over expecting a different result means something don't they?
Anyway the overload switch feeds the hydraulic pump etc as well as the spindle drive field current. I finally disconnected the field current wires and tried again just running hydraulics and ancillaries. No problem with no thermal trip.... I am now making the assumption there is too much current draw on the spindle field circuit - something I know nothing about and sounds like it could be expensive. :bugeye:
The other option could be the overload switch faulty but I suspect not. I have attached a few photos of the spec plates on the motor and field drive. If anyone knows anything about what I now need to do I would certainly appreciate the help....  As you will see it is a Siemens motor.
cheers

Jeff

JeffK:
Woops - just noticed I put the same (upside down) photo in twice :doh: One of those days....
Here's the right one.

awemawson:
Oops  :scratch:

Had it been a field drive for a Mawdsley I know where there is a spare, but yours seems to be a Siemens.

I don't often say this, but your pictures are too small to get the detail - I'm usually banging on asking people to make them smaller !!  If you load them up at 640x480 or 800x600 the writing becomes readable.

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