I have an 8' bed 4-spd direct drive 3 phase Blount patternmaker's lathe. In its recent past before I got it, the controller got damaged and then fixed. Somehow, the wiring got rearranged and it no longer is correct. With 14 motor wires and 3 input legs, simple easter-egg troubleshooting is not really an option. I have done some calculated swapping but pretty much exhausted all the obvious possibilities. Does anyone have such a beast, or know someone else who does? A picture of the configuration of the switch would help considerably. A manual would be a godsend. Thanks. Ed.
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Blount lathe controller wiring
- Thread starter ed thomas
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John: Thanks. I did post the same question first over there and got a whiff of guidance for further help, but nothing concrete yet. I thought I'd widen the net by posting here. By asking several places, I'm getting hints that are starting to help it make sense even though no one yet seems to have specific answers. Thanks for responding!
controller problems
Ed
I didn't think there would be another Blount lathe within hundreds of miles. You are just down the road. I also am having problems with my speed controller so if you can find a schematic, let me know. I think most had one pasted on the inside cover but mine is unreadable. Here are some thoughts that I had about locating the problem that are no more than guesses. if you live out in the country like I do your probably running your lathe on a phase converter if that is a static converter you are just running on 2 phases. also most rotary converters have balancing capacitors between the phases that might cause a problem. If you are lucky enough to have 3 phase service you might be Delta connected (has one high leg of higher voltage)
If your controller is the same there are 4 rows of plastic caps covering contacts. they have holdown nuts at either end. they can only be put on one way because of the registry pins, but Im not sure the caps are identical. there are jumper wires on the inside of the caps. my theory is maybe some one took the caps off to clean the contacts and replaced them in the wrong positions. It seems more likely than someone moving wires on this complex arrangement.
Ed
I didn't think there would be another Blount lathe within hundreds of miles. You are just down the road. I also am having problems with my speed controller so if you can find a schematic, let me know. I think most had one pasted on the inside cover but mine is unreadable. Here are some thoughts that I had about locating the problem that are no more than guesses. if you live out in the country like I do your probably running your lathe on a phase converter if that is a static converter you are just running on 2 phases. also most rotary converters have balancing capacitors between the phases that might cause a problem. If you are lucky enough to have 3 phase service you might be Delta connected (has one high leg of higher voltage)
If your controller is the same there are 4 rows of plastic caps covering contacts. they have holdown nuts at either end. they can only be put on one way because of the registry pins, but Im not sure the caps are identical. there are jumper wires on the inside of the caps. my theory is maybe some one took the caps off to clean the contacts and replaced them in the wrong positions. It seems more likely than someone moving wires on this complex arrangement.
A standard 3 phase motor with many leads has 12 leads, not 14. They need to be divisible by three. By some chance you could have a simple loop of two leads that detect overheat. Are there numbers on the leads? If so what are the numbers? What kind of controller do you have?
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Fourteen leads means that two of the leads are connected to a thermal sensor. The other twelve leads are for wiring the motor for one of two voltages -- most likely 230/460 VAC, but for fractional HP motors less than 1.5 HP, it might be 115/230 VAC.
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The motor wires are either numbered or color coded. The motor nameplate gives the connections for the motor leads
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Bill B,
Can't recall ever seeing a multi speed three phase motor with multi voltage capability. I suppose they might be out there, but the number of motor leads would be unwieldly.
I do recall seeing a large (100 hp) cooling tower fan motor with two speeds that was to be started on slow, and then switched to high as the startup proceedure that had the phase wrong on the high speed. When it went from low speed to high speed, it reversed direction and twisted the mounting frame of the motor and nearly jumped loose.
I have only dealt with two speed motors, so just speculation here; with four speeds, and three wires for each speed, it would need 12 wires (motor leads).
If using an Ohmeter finds sets of three wires that are joined together, but isolated from the other leads, then my guess is that the sets of three wires would comprise one set of windings for a speed. Anything other that that, I haven't a clue.
Can't recall ever seeing a multi speed three phase motor with multi voltage capability. I suppose they might be out there, but the number of motor leads would be unwieldly.
I do recall seeing a large (100 hp) cooling tower fan motor with two speeds that was to be started on slow, and then switched to high as the startup proceedure that had the phase wrong on the high speed. When it went from low speed to high speed, it reversed direction and twisted the mounting frame of the motor and nearly jumped loose.
I have only dealt with two speed motors, so just speculation here; with four speeds, and three wires for each speed, it would need 12 wires (motor leads).
If using an Ohmeter finds sets of three wires that are joined together, but isolated from the other leads, then my guess is that the sets of three wires would comprise one set of windings for a speed. Anything other that that, I haven't a clue.
There are currently manufacturers of 3 phase multi speed motors. The basic idea is to have lots of extra poles. For example a 4 pole motor on 60 hz runs around 1850 RPM while a 2 pole motor runs around 3700. This basic concept can be extended to more poles. By tricky wiring you can get various pole combinations that yield multiple speeds. It becomes increasingly impractical to manage as the number of poles rise so I don't believe anyone makes more than 4 speed motors. You might be able to get a manual for a current motor and try to apply that information to your motor.
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Dale, I overlooked the multispeed part of the OP. I was primarily addressing a post prior to mine about the number of leads on a three phasemotor with the same assumption of dual voltage operation. Sorry about the confusion. This dang iPhone is like browsing through a keyhole.
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Holmger, you're a bit high on motor speeds. The synchronus speed for a two pole motor is 3600 RPM and in order to produce work, there is a slip frequency that is directly proportional to load torque. This means that in the real world, the maximum speed would be more like 3500 RPM and for cheap motors it might be as low as 3450 RPM. Similarly, the sync speed of a four pole motor is 1800 RPM and practical speeds would range between 1700 and 1750 RPM.
There are two limiting factors in building multispeed induction motors -- price and price. As the number of poles increase, the difficulty of cramming wires into very narrow slots becomes very labor intensive and manufacturing the laminated stack for the field also becomes increasingly difficult. All this extra manufacturing processes and labor mean that unless you are NASA, you can't afford it.
There are two limiting factors in building multispeed induction motors -- price and price. As the number of poles increase, the difficulty of cramming wires into very narrow slots becomes very labor intensive and manufacturing the laminated stack for the field also becomes increasingly difficult. All this extra manufacturing processes and labor mean that unless you are NASA, you can't afford it.
Ed,
I have a Blount patternmakers lathe, 24" x 65" BTC. It has a 2 hp, 4 speed three phase motor and has the controller installed and runs fine. It has 14 wires as you describe and I suspect a wiring diagram from it will be what you need. I am located in the eastern tip of Tennessee if you wanted to drop by. I can make a wiring diagram for you if you desire that. I think I started one several years ago when I installed a VFD on the lathe, now if I can just find it.
I am rarely on this forum but will try to check every few days to see if you have responded.
Bruce Norton,
Kingsport, TN
I have a Blount patternmakers lathe, 24" x 65" BTC. It has a 2 hp, 4 speed three phase motor and has the controller installed and runs fine. It has 14 wires as you describe and I suspect a wiring diagram from it will be what you need. I am located in the eastern tip of Tennessee if you wanted to drop by. I can make a wiring diagram for you if you desire that. I think I started one several years ago when I installed a VFD on the lathe, now if I can just find it.
I am rarely on this forum but will try to check every few days to see if you have responded.
Bruce Norton,
Kingsport, TN