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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Testing 3PH motor ??
I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but
there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee |
#2
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Testing 3PH motor ??
Are you sure the motor doesn't have a junction box where the 3 wires come out?
Bob Swinney "Chief Mcgee" wrote in message ... I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee |
#3
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Testing 3PH motor ??
On 2010-03-30, Chief Mcgee wrote:
I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee out of where exactly do three wires come out? I would look into the control box, see what is the control transformer doing and what is the voltage of the contactor, that should be proof enough of the motor voltage. i |
#4
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Testing 3PH motor ??
"Chief Mcgee" wrote in message
... I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee Well, if you can't find more wires, I would just put 220-240 on it, see how it sounds. If the contactor just buzzes on 240, then it proly is 440. -- EA |
#5
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Testing 3PH motor ??
"Robert Swinney" wrote:
Are you sure the motor doesn't have a junction box where the 3 wires come out? My Clausing 6903 had the wires to change from 480v to 240v buried inside the liquidtite flex. I was worried for a while. I sure didn't want to buy a 3-5 KVA 3 phase transformer. http://wess.freeshell.org/Clausing_6903_motor_leads.jpg You can see how the wires tapered from the splices. **** poor wiring practice. GM Saginaw electrician did the deed according to the property tags. Currently running happily on 240v from my rotophase. Wes |
#6
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Testing 3PH motor ??
On Tue, 30 Mar 2010 15:45:27 -0500, "Chief Mcgee"
wrote: I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee Check the voltage rating on your contactors and/or what voltage position the control transformer input is set at. Gunner "First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity. This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost |
#7
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Testing 3PH motor ??
Existential Angst wrote:
"Chief Mcgee" wrote in message ... I have a 20HP, 3ph motor on my lathe. The label says it is a 220/440, but there are only 3 wires coming out of it. I assume it was rewired straight some time in the past. Motor appears to be 1940's model. Is there a way to test the motor to tell if it is wired for strsight 220 or 440 ? The controls have 440 stickers on them. So I assume the motor has been rewired for 440. But is there a way to test for sure? thanks, McGee Well, if you can't find more wires, I would just put 220-240 on it, see how it sounds. If the contactor just buzzes on 240, then it proly is 440. ** 20 ** Hp? If you connect a 20 Hp 220 V motor to your home mains, you may well need a truck from the power company to get the lights back on at your house. The run current of such a motor, even at no load, would be around 66 Amps on 3-phase mains. Trying to run it off single phase (not sure that's what you are trying to do, so this message may be way off the mark) the line current would be HUGE, and the starting draw would be a couple hundred amps. If you do have 3-phase 240 V power there, and the motor is set for 440, and assuming the contactors will pull in, you would get a slow start that should be pretty obvious. It would take maybe 5-10 seconds for the motor to accelerate even with the lathe gears in neutral. With the right voltage, the motor should accelerate to full speed well within one second. Jon |
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