Thread: PRM lathe...Help...Help...

Hello All,

Im new here. Looking for some assistance in wiring my new to me PRM lathe. The lathe was wired for 110v when I bought it and it worked fine. I decided to switch it to 220 because I did not have a 110v outlet in my garage that could handle the load. Also I just needed 220 in the garage anyway. Long story short, I wired it according to the diagram I have attached and it sounds like hell for a few seconds and it trips the breaker. Allow me to answer your first question...the capacitors are good. When wired according to the diagram there are no two wires coming from the cabinet to the motor that equal 220 between them when measured with a multimeter. When you read the diagram the only wire coming from the cabinet to the motor that has 120v is U1. It says nothing about a second line in...any help would be appreciated. The transformer has been switched for 220v also. I would also be happy to answer any other questions you may have if it will help me out. Thanks for your time.

Jeff

In the U.S. you need two hot wires to get 220/240VAC single phase. If you only have a single 120V line in you are not wired correctly. You should have hot wires connected to the wires marked 'L' and 'N' in your diagram for 220V. They will then connect through the circuit to 'U1' and 'U2' on the motor. Some 220/240 circuit diagrams are labeled this way ('L1' and 'N' instead of 'L1' and 'L2') - it can be confusing to those not familiar. This is common on European machines especially as their electrical system carries the 220V on one hot line and a neutral. Make sure you have 220/240V across those two input wires or you will obviously not get the 220/240V at the motor. You won't use a neutral wire in this setup.

Thank you for your reply. So I do have 240v coming in at the L and N 120 each. But the wiring goes up to a transformer and then to several relays before coming back to feed the motor. At the wires coming back to feed the motor I only have 120v. Now IÂ’m wondering, based on what you said about Europe, is it even possible to run this lathe on 240v without a neutral?

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What About Bolton And Prm Lathes | The Hobby-Machinist

Originally Posted by jqfire

Thank you for your reply. So I do have 240v coming in at the L and N 120 each. But the wiring goes up to a transformer and then to several relays before coming back to feed the motor. At the wires coming back to feed the motor I only have 120v. Now IÂ’m wondering, based on what you said about Europe, is it even possible to run this lathe on 240v without a neutral?

No it doesn't, unless your schematic is not correct. The power comes in and through a single relay/starter before going to the motor. That starter will be controlled by your forward/reverse switch. It sounds like maybe you should call an electrician. And again, the two hot wires should be connected to the points marked 'L' and 'N' on the 220 schematic. It will run just like it's supposed to that way unless you have miswired the machine or something is damaged. I think this may be beyond your abilities, it doesn't sound like you are very familiar with electrical work.