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Bridgeport motor VFD

KevH

Plastic
Joined
Oct 28, 2018
I have a 1 HP Bridgeport motor [English Electric Co. - 220/440V] I would like to run from a VFD. It has only 3 wires coming from the windings into the drum switch. I would like to bypass the drumswitch and run from a 240V 1 phase [UK supply] to a 240V 3 phase output VFD.


Would it be a simple case of wiring from U,V,W connections of the VFD to any of the 3 wires giving a delta connection?. All the YTvideos Ive seen seem to show the terminal blocks with jumper plates

Any help appreciated
 
Ditto what Johansen said...

English Electric... 220/440 you say? that one's not familiar to me, so don't take the following for anything more than you paid for it:

My Bridgeport J-head mill has the 2hp 'pancake' motor... and I don't recall off the top of my head where the connection change is made to switch it between ranges, but I believe it's in delta for low, Y for high.

The 'pancake' motor is an interesting load... when you're programming your VFD, if yours is like mine, the VFD will 'act' like the motor is quite a bit bigger than it's ratings. I run mine off an Allen-Bradley 1305 type AA12A (240v, 12A) and it does fine on single-phase... I leave the belt in middle position, and rarely need the backgear... I just flip the switch and turn the knob. ;-)
 
Yeah, provided its wired for 220. If its wired for 440 you will need to find the the other 6 wires.

Ive taken the end plate of and there's def only 3 wires [black] coming out, any ideas? The mill is wrapped up from the weather in parts ready to go into my workshop. Ive only got the motor off to check for the moment but is it possible the wiring is configured in the control box on the side of mill


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that is a wye/delta motor. there should be 3 more wires somewhere. (perhaps someone rewound it?)

If it is wired for 380v then when running on 220 from a vfd you'll basically get up to half a hp out of it, that might be enough for you.

You can however program the vfd for 440v 60hz and you'll get the full 3.9 foot pounds of torque up to 30hz or about half the nominal rpm (it seems to have a rather high slip, 1350 rpm?). you can also boost the 220v input to your vfd to as high as the vfd is rated for, which might be 260-270 vac. its not much more but you'll get full torque up to ~35hz in such a case.

anyhow,it may be wound for 220v and you won't have these problems.
 
that is a wye/delta motor. there should be 3 more wires somewhere. (perhaps someone rewound it?)

If it is wired for 380v then when running on 220 from a vfd you'll basically get up to half a hp out of it, that might be enough for you.

You can however program the vfd for 440v 60hz and you'll get the full 3.9 foot pounds of torque up to 30hz or about half the nominal rpm (it seems to have a rather high slip, 1350 rpm?). you can also boost the 220v input to your vfd to as high as the vfd is rated for, which might be 260-270 vac. its not much more but you'll get full torque up to ~35hz in such a case.

anyhow,it may be wound for 220v and you won't have these problems.

THanks for your help! so basically you are saying it s not a dual voltage anymore and will only run on what ever its wound for? I bought it from a machine dealer and it was running on their 415v supply,
 
THanks for your help! so basically you are saying it s not a dual voltage anymore and will only run on what ever its wound for? I bought it from a machine dealer and it was running on their 415v supply,

if its been rewound and there are only 3 wires then its whatever it was rewound for. could be 415/50hz, it could be something else too, but unlikely since in the UK isn't almost all 3 phase delivered as 380 to 420 volts 50hz?


anyhow my point is you can program your 220v vfd for 440v 60hz (or 220v 28hz) and have a full motor torque up to half its design rpm, above that the torque will drop off.

you may be able to find the Y point in that winding and rewire it for delta if you're willing to dig for it. how difficult would it be to replace the motor?


Another option is to just buy a 440v vfd and find a transformer. you can use 220v isolation transformers as an auto transformer to boost the voltage to 440.
For a 1 hp motor a 1kw single phase isolation transformer will deliver 2kw worth of 440v power when connected as an autotransformer, and as such it would be sufficient to drive a 440vfd and 1 hp motor.
If you buy a 240:480v transformer it would need to be 2KW if you intend to run the motor at full load continuously and will cost about twice as much as a 1kw 220v isolation transformer.
 
Motor replacement might be best option or 240v 1 ph input to 415v 3ph output VFD. Anyway , thanks for your help
 
I've got several machines' motors wired for 480 3ph, but I run them off 240v single...

480:240v single-phase transformer wired backwards (mains to the 240v primary). The primary leads present 480v single phase to terminals A and C of a VFD (terminal B unused). Program the VFD to ignore phase loss (if it has such a protective feature), and size the VFD to be a little bigger than the motor (for a 2hp motor, I'd go 3hp VFD).

Works great...

And if your motor is a 380v, just program your VFD's motor profile to whatever your motor's tag indicates.

For my J-head, I have mine programmed to run the motor to about 140hz... plenty of spindle speed without changing belts, and it'll present plenty of torque all the way down to a standstill...
 
What the OP has to work with is presumably single phase standard UK power, which is 240V line to neutral. That is one line of standard 415V 3 phase. There are RPCs which make that into 415V L-L 3 phase, per the recent thread on the monarch that won't start. There may be VFDs which can do that also, but I know little about them. At least one UK company was modifying 400V class VFDs to voltage double so as to work with 240V input. I had heard that they had to stop, but that was not a reliable source of info. As for factory-made versions, I am not aware of any at the moment, but I am not as "connected in" to that business as I was a few years ago. You might check the Invertek line, they have a good number of useful versions, and are made locally in Wales.
 
There are plenty of 240V single phase to 240v and 415v 3 phase VFDs available in UK
 
An older 3-phase 415v input VFD can often be hacked to "think" it has 415 in when you feed it 240, I run an ABB ACS300 series which has the neutral input taken to the board where the two banks (in series) of reservoir capacitors meet, live taken to two of the phase inputs to share the input current - it's a hack, invalidates the long-expired warranty and any approvals and probably causes Gerbil Warming, but it runs my very odd and irreplaceable 3-speed motor pretty well...

Dave H. (the other one)
 
An older 3-phase 415v input VFD can often be hacked to "think" it has 415 in when you feed it 240, I run an ABB ACS300 series which has the neutral input taken to the board where the two banks (in series) of reservoir capacitors meet, live taken to two of the phase inputs to share the input current - it's a hack, invalidates the long-expired warranty and any approvals and probably causes Gerbil Warming, but it runs my very odd and irreplaceable 3-speed motor pretty well...

Dave H. (the other one)


That wiring converts the thing to a voltage doubler, just as the one company I knew of was doing (and may still be).

Doubled 240 is a bit higher than 415V, but most VFDs in that voltage class will take it. Refer to manual for definite info on input voltage range that is allowable.
T
 








 
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