- Joined
- Dec 23, 2019
- Messages
- 1,138
Posting this as I feel it's likely to be useful to other members.
To cut a long story short, I bought a Bridgeport with the J head and 2hp "pancake" motor. I foolishly looked at the two speed switch and thought "great, it's a star/delta switcheroo for speed selection. If I run it 220V in delta all will be fine" and ordered a VFD. How wrong I was.... The motor is 380-415V only, and set up with a "Dahlander" connection, which is essentially series or parallel star for the speed selection. Research showed that this doesn't respond well to running at 220V. Even worse, people that seem to know what they're talking about (on another forum) suggested that there's no way to rewire it - without a full rewind - for 220V 3 phase.
Now, I'm not the type to take that kind of thing laying down... They're almost right: there's no way to wire it for 220V with the wires you're presented with out of the motor casing. You can, however, change the connections between the windings internally, and actually quite easily. Yes, I know: there are inverters available that do single phase 230V to 380V three phase, but they're expensive and/or inconvenient, especially if you want variable frequency and something that's not an import house igniter.
A video tells a thousand words:
Not trying to drive traffic to my channel (it's waaay below the monetising threshold in any case).
I hope it's useful! It's literally dozens of hours of research, reasoning and tinkering, so hopefully it saves someone else the time. I've no doubt that the same can be applied to many other motors. I've since also successfully converted a 3 phase bench grinder from internal star connection to delta, and motors no longer seem so scary.
Cheers!
To cut a long story short, I bought a Bridgeport with the J head and 2hp "pancake" motor. I foolishly looked at the two speed switch and thought "great, it's a star/delta switcheroo for speed selection. If I run it 220V in delta all will be fine" and ordered a VFD. How wrong I was.... The motor is 380-415V only, and set up with a "Dahlander" connection, which is essentially series or parallel star for the speed selection. Research showed that this doesn't respond well to running at 220V. Even worse, people that seem to know what they're talking about (on another forum) suggested that there's no way to rewire it - without a full rewind - for 220V 3 phase.
Now, I'm not the type to take that kind of thing laying down... They're almost right: there's no way to wire it for 220V with the wires you're presented with out of the motor casing. You can, however, change the connections between the windings internally, and actually quite easily. Yes, I know: there are inverters available that do single phase 230V to 380V three phase, but they're expensive and/or inconvenient, especially if you want variable frequency and something that's not an import house igniter.
A video tells a thousand words:
Not trying to drive traffic to my channel (it's waaay below the monetising threshold in any case).
I hope it's useful! It's literally dozens of hours of research, reasoning and tinkering, so hopefully it saves someone else the time. I've no doubt that the same can be applied to many other motors. I've since also successfully converted a 3 phase bench grinder from internal star connection to delta, and motors no longer seem so scary.
Cheers!
