- Reaction score
- 11
Old
Discuss What kind of motor is this? in the UK Electrical Forum area at ElectriciansForums.net
That reminded me that there was a large cast iron oil filled motor starter for a wound rotor motor in a local laundry basement that once fed a compressor, sadly the motor and compressor are long gone, but the air receiver sill remains. Still full of (probably hazardous) oil, had a manufacture date of 1949 IIRC. I wonder if it is still there. Had a little hand wheel to operate the variable resistors for starting, still turned ok. Fed from a large adjacent Memajor switchfuse all wired in poly butyl jute cables in 1 1/2 steel conduit.Repulsion type,with brush gear and com, used on early type compressor needing good starting torque.
You got it exactly, although it didn't blow a fuse, it just cut out at the switch and I had to start again with much mockery from the othersCould have been some combination of tap changing and star delta.
But in that era, the aforementioned slip ring induction motor with variable rotor resistance would be a good candidate - I'm assuming it was started unloaded but with a massive inertia of drive lines & pulleys to wind up.
With a large resistance across the brushes, the rotor current is limited - so torque is vastly reduced, but so is stator current.
So did the first notch set it slowly tunning up like there's all the time in the world ? Then the next notch add a bit of urgency ? Until it's up to speed and can go to the last notch where the rotor is shorted and it runs as a normal squirrel cage motor.
Presumably, you had to learn by ear how fast it needed to be running before you could go to the next step without blowing fuses ?
Reply to What kind of motor is this? in the UK Electrical Forum area at ElectriciansForums.net
We get it, advertisements are annoying!
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.