Series 61 Wiring Question/ Issue

Hey Everyone,

So as I make progress on my lathe I finally got around to getting the lathe wired up. I had it running but it was running backwards. I switched 2 wires and it made awful noises and wouldn't spin. Looking into it, I found it was wired for high voltage (480) so today I took the motor out and wired it for the low voltage setting. Now the motor switch won't latch and just arcs at the contactor when I press the button, obviously this is not good. I am thinking that one of the wires may have been mismarked? Is there anything else that needs to be looked at besides the motor to wire at 230v? Any info will help.

Thanks!

The motor starter will not work when you change voltages unless you replace the coils and heaters. I decided it was cheaper and easier to replace the starter on my lathe. I went with a Square D reversing starter. I was able to buy the starter, coils, and heaters on eBay. Square D sent me wiring diagrams so that I could wire it up.

A standard problem is if you have a RPC, then make sure the control wiring is NOT connected using the generated leg. It is unstable during starting. To nt1953's points, if the motor was wired for 480, then the control is also wired for 480. Either there is a transformer between the line and starter, or the starter is wired for 480. Don't forget to change the heaters.

Tom

Doing some quick research it may be that someone already had changed the one in this? See attached picture. Its a Square D 8736. Only thing is it says its rated for 5hp in 220v. Mine is 7.5hp.



Picture quality diminished once it was attached.

TDegenhart said:

A standard problem is if you have a RPC, then make sure the control wiring is NOT connected using the generated leg. It is unstable during starting. To nt1953's points, if the motor was wired for 480, then the control is also wired for 480. Either there is a transformer between the line and starter, or the starter is wired for 480. Don't forget to change the heaters.

Tom

Click to expand...

Hey Tom,

Could you explain a little more on the generated leg not on connected to the control wiring? I currently have my generated leg as L3.


Also, my heaters are b28 but according to the manufacturers chart I need a b32 for my FLA on 240v so I will get those ordered. I do have a transformer in the cabinet but it's wired to take 3 legs off the starter to go a secondary starter for the coolant pump. At least this is what it appears following the wires quick.

viane said:

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Could you explain a little more on the generated leg not on connected to the control wiring? I currently have my generated leg as L3.

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Click to expand...

Two of the three incoming phases are used in the circuit that powers the coils that operate the starter. Those two phases need to be the real phases when you're using a rotary phase converter, as the artificial phase can do odd things during startup and keep the starter from closing. As Tom said, the voltage of the coils needs to either match the line voltage or a transformer needs to be used to change the control voltage to what the starter needs to operate. In your case, you would need a 240 to 480 transformer to step up the voltage. It may be that the transformer that you have for the coolant pump will do the trick. What you may have is a machine with a 480 starter for the spindle motor and a 240 starter for the coolant pump. If that's the case, move the transformer from the coolant pump starter to the spindle motor starter, connecting it so that instead of stepping 480 down to 240, it steps 240 up to 480. I hope that makes sense.

The Square-D 8736 starter appears to still be supported. There are coil conversion kits listed for it. Contact Schneider (the manufacturer of the Square-D line) and I'm sure they can help you out.

Cal

This makes complete sense, thank you! It appears that L1 and L3 are used to power the coil. I will adjust to make the generated leg L2. I will look into the correct voltage coils. The correct Heaters are on their way now. Thanks everyone for the help! Once I get it running I will report back.

You state your starter is rated at 5 hp max. You will need to purchase a larger starter to run your motor. Make sure you buy one with the correct coil for your voltage. Check to make sure your start/stop isn't being run through a transformer to lower voltage. My Series 61 is wired with 115V coil, reversing Westinghouse starter, that was originally supplied by 440V. When I rewired the motor for low voltage, I had to change everything to run on 250V input. New heaters, and I also had to rewire the control transformer (which also starts my coolant pump and my lights) to low voltage instead of high. Easy enough to do, but nothing will run if your transformer is still wired to high voltage (which it probably is).