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3 phase starter circuit

madmachinst

Stainless
Joined
Jan 15, 2007
Location
Central FL
NO one including him ever put a clamp on to their power line while running the machine. Originally I remember him saying he used a 60 amp breaker. Now he is running it on a 100 amp breaker. I even put a thread up in the Mazak subforum and no one ever replied.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
If you want to find out if your 50 hp motor will act as a generator without caps attached, belt up the pony motor, spin the idler up, and measure the voltage between connection points for L1, L2 and L3. If you are curious, add some caps and try it again.

You mean, like a real actual experiment?
 

J_R_Thiele

Stainless
Joined
Jan 22, 2003
Location
Columbia Missouri
Yes, an actual experiment.

I was not surprised that my 10 hp idler with caps generated some voltage. I was surprised that the voltage got up in the 250 range, and would run a coolant pump.

Theory is nice. Reality is definitive.

Or if you prefer: Seeing is believing.

This would also give an idea of how long it will take his 2 hp pony motor to spin up the 50 hp idler, which he will eventually need to know.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
...
This would also give an idea of how long it will take his 2 hp pony motor to spin up the 50 hp idler, which he will eventually need to know.

If my experience with a 1/8 hp pony motor starting a 5 hp conveter, the answer to that question (I'm betting here) is about two seconds.
 

JST

Diamond
Joined
Jun 16, 2001
Location
St Louis
Yes, an actual experiment.

I was not surprised that my 10 hp idler with caps generated some voltage. I was surprised that the voltage got up in the 250 range, and would run a coolant pump.

Theory is nice. Reality is definitive.

Or if you prefer: Seeing is believing.

This would also give an idea of how long it will take his 2 hp pony motor to spin up the 50 hp idler, which he will eventually need to know.

Motors with capacitors are used in many places as a very robust generator. I've made them. If the (in)correct capacitor is used, the voltage can be very high. Motor needs to be "flashed" to start the generation. It takes a bit of residual magnetism to start everything going.

The generation into the capacitors can really suck power. I had one setup where I miscalculated the capacitors and it bogged the test driving motor down with no external load on the generating motor. That test motor was the same nominal power as the generating motor was!
 

madmachinst

Stainless
Joined
Jan 15, 2007
Location
Central FL
I'm choked up money wise and wondering if I should get the new 2 HP motor from automation direct or find something at a scrap yard. Local place only had 3 phase stuff. Mind you that 2 HP will cost me what the 50 HP did ( shipping was more than the motor).
 








 
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