Aren't the Hardinge brake solenoids AC and pull the brake off? If so, then dirt or similar stopping the solenoid from pulling the brake arm all the way will cause a higher current than normal. The inductance of the solenoid goes up once the air gap is closed, lessening the current in the coil.
Just a thought...
Mark Rand RTFM
Correct. And there is a lever allowing the solenoid to be manually pulled out of braking position and locked there. So one would assume that in that position..the heat builds up as long as the lathe is powered up and over the years....
This brake unit is intergral to the motor, in an elongated sheet metal end cap, not like the brakes mounted to the motor plates on regular Hardinge machines and snubbing against the motor drive pulley.
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3
USA cheapest best way yo go
scrap 3 phase motor install 2 phase (220) motor made in USA. Cheapest and best way to go
Ned, I understand about the 1/6 power loss due to running the 575V motor off 480V , but why tell the VFD it's a 50 cps. motor? I thought Canada was the same as the US, 60 cps. line voltage?
Garrett Fulton fired this volley in news: snipped-for-privacy@googlegroups.com:
I personally think it's a fool's errand. Those motors - in that form- factor, are available new and rebuilt in 230V ratings. They're not all that costly.
Lloyd
That thread's old enough that I don't remember writing that, but I can explain it. Simple open loop VFDs are often called volts/Hz drives because they adjust their output to maintain the voltage to frequency ratio constant as the frequency changes, which in turn keeps the motor current more or less constant. So if you tell the drive the motor's nameplate says 480V / 50Hz, the drive will output 480V at 50Hz, instead of the default (in the US) 480V at 60Hz.
480/50 = 575/60
Okay. I understand. Thanks for the time.
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
Put a decent 3-phase inverter duty motor on there, and you can use the VFD for what it was intended to do!
F**K step-pulleys!
Lloyd
================ Fleabay has several listed. free freight ~400$US. (three phase)
In a hobby shop you most likely won't need full power so for cheap see
but see
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
I have not seen any over about 3/4HP that will go 110 1-ph to 230 3-ph. But there are plenty of them up to 3hp, and a few up to 5hp that will do
230 1-ph to 230 3-ph.You can also usually get away with derating larger 3-phase input ones by
1/3 when handline single-phase input... but not all brands, so be careful on that.LLoyd
I got a good deal on one like that a number of years ago. I thought it was a good deal until it arrived and I found that it needed a separate programming module! The modules were rare and expensive, but I got one, cheap.
The linked VFD might be programmable with a PC, or it might need a module.
Bob
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