About to buy a Clausing Colchester 1336 Engine Lathe (Master Mark I)

[mksj]

The question would be if there is any benefit to having the VFD setup for both motor speeds, in this case probably not because it is a half speed motor and the Hp is 1.5Hp vs 3Hp at full speed. There is usually additional torque going from an 4P to an 8P. The lathe uses a multiple section rotary switch to change both the wiring for speed and direction, and if I recall this lathe uses a clutch drive system. At the end of the day, I recommended that he either go with an RPC or a Phase Perfect. Phase Perfect now has three low cost models at 3, 5 and 7.5Hp and they are priced competitively with the RPC. Price wise this is also competitive to a VFD install and in this case it may be a bit more complex to redo all the wiring/controls.

I did a lathe install with a dual speed Dahlander motor for a Chinese lathe, I configured my own rotary switch (something like 12 sections), which would switch the motor windings and the input on the VFD for the 2nd motor. It went through a center stop position. Was a lot of work and the motor never performed well. I scrapped everything, got a vector motor for the lathe, and it worked wonderfully. I have also tried other two speed motors and they often do not do well unless it is a constant Hp and then I just run it on the higher pole setting with over speeding the motor.

Two speed motor and replacement vector motor.

 

[Beckerkumm]

I don't believe the 1336 had a clutch. There was an air lock switch that started both the motor and the spindle when a lever was operated. When the lever was turned to off, both the motor and spindle stopped. Pushing the lever farther operated a brake. Shifting motor speeds required the motor to be off so it isn't like the Smart Brown that allowed swapping motor speeds on the fly.

I agree that an RPC or PP is the way to go if keeping the existing motor but you want to be sure the motor is good. A vfd and motor conversion is an all in proposition and makes the money spent for the RPC a waste for this machine. If the motor is good, it should be very smooth at low speed. Here is a three speed motor which is unusual but they are still available. Not for the faint of heart or thin of wallet though.

Dave

 

[bradpj53]

I will write up an account of my small adventure in bringing this machine home, but I have a burning electrical question that I can move to the Electrical Forum if needed but one question is specific to Colchesters. I have successfully wired up a Phase Perfect 3HP Unit and have current on all 3 legs. The lathe will not run with the start lever in the proper up position unless the contactor is manually engaged; then it runs until the lever is pulled down. I’m wondering if this is an issue with the starter (I have continuity across the coil) or there there are cut-out switches I don’t know about that are preventing starting. I have the gear cover in place. Starter is an Allen Bradley 709.

 

[bradpj53]

In reviewing the literature the feature I called "cut-out" is known as an interlock, preventing powering up at a time that would increase injury or damage risk.

Brad