Variable speed single-phase Bridgeport conversion

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DFWKen
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Variable speed single-phase Bridgeport conversion

Post by DFWKen »

Well, I'm currently aesthetically restoring a Bridgeport Series 1, J-head step-pulley mill. This is for my home shop (to keep my lathe company). Like most residences in the Dallas area, we have single phase power. I know, I know . . . just get a rotary converter abd be done with it. But, couldn't I apply the cost of the converter to the purchase of an SCR-controlled motor that utilizes single-phase power instead?

I went through hundres of threads on this forum as well as using the Search function before posting this "chip-sweeper" question. Please have mercy with my ignorance. Great forum, by the way. I can see myself browsing around here for hours and hours.

Ken
dkinzer
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Location: Beaverton, OR

Re: Variable speed single-phase Bridgeport conversion

Post by dkinzer »

I recently converted my bench mill from a single phase 110V motor to a 3-phase motor and added a VFD to drive it which is being powered by 220V single phase. I can now instantly dial any speed between zero and 200% of the speed of a given step pulley configuration - very cool!

I got my VFD from an eBay seller named driveswarehouse. It's the same model as in this auction:
Hitachi 1HP VFD

You might need a bigger one - my bench mill only has a 3/4HP 3-phase motor.

Don Kinzer
Portland, OR
Don
Marty_Escarcega
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Re: Variable speed single-phase Bridgeport conversion

Post by Marty_Escarcega »

VFD (Variable Frequency Drive) http://www.dealerselectric.com has some great buys on the TECO Westinghouse unit. Dead simple to operate.
Besides, the Bridgeport has a motor with a very long shaft.
VFD will give you variable speeds.
Marty
"Jack of all Trades, Master of None"
Scott
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Re: Variable speed single-phase Bridgeport conversion

Post by Scott »

Marty,
I bought a Teco 2hp from them.They have very fast shipping,and good prices.Just not as good as your last ebay vfd deal.Did that one work?It gets real spendy in the size you got.
Marty_Escarcega
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Re: Variable speed single-phase Bridgeport conversion

Post by Marty_Escarcega »

Scott, I just took delivery of it yesterday. I've not had a chance to check it out....
Looked good? [img]/ubb/images/graemlins/grin.gif"%20alt="[/img]
"Jack of all Trades, Master of None"
fredwhite
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Location: Greater Kansas City Mo

Re: Variable speed single-phase Bridgeport conversion

Post by fredwhite »

I run a variable speed DC motor system on a lathe, two drill presses, and a step pulley Bridgeport.

I'm very pleased.

DC versus VFD may be a "Ford / Chevy" discussion.
DFWKen
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Thank you, guys. I've made my decision

Post by DFWKen »

I emailed each company last night and got replies from both.
One of the companies (Drives Warehouse)is right here in Dallas. Their Hitachi model which is capable of up to 2hp costs $340.00 + tax but no shipping since I can pick it up.
http://www.driveswarehouse.com/product_ ... ucts_id/44

The other one from Dealers Electric (TECO/Westinghouse FM100-202-N1 2 $246.00) appears to be similar and only costs $246.00.

All other things being equal, I'll go with the TECO/Weshinghouse product.

I'm looking forward to enegerzing this machine.
Matt_Isserstedt

If that's too much money...

Post by Matt_Isserstedt »

I can tell you how to start and run that Bpt off your single phase with an $8.00 capacitor, a momentary pushbutton and a drum switch and a few feet of SO cord.

Of course you'll have to live with the mill's variable speeds or step-pulley offerings (motor will be a constant speed).
DFWKen
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Hmmm, like a start cap on one of the phase inputs?

Post by DFWKen »

I assume that you use the capacitor as a "start" capacitor, feeding two phases directly and the third out of phase from one of the others via the capacitor. Then once the motor is running, you remove the cap from the circuit and it continues on the two directly-energized phases?

I'd like to see or hear how you'd wire it up. I might try it to power the mill up while waiting for the VFD.

I just read a newer post in this forum and clicked the links about phase converters. As a 25 year air conditioning technician, I should have known that. (chuckle). Thanks for getting my brain in gear.

Ken
Matt_Isserstedt

Re: Hmmm, like a start cap on one of the phase inputs?

Post by Matt_Isserstedt »

Yes, you've got it. The drum switches two poles to the motor, but the motor will hum with a locked rotor.

The momentary switch connects L1 or L2 to the capacitor then L3 for starting. Release the switch when the motor starts to turn.

You can run well enough to play with the machine before the expensive toys get there [img]/ubb/images/graemlins/smirk.gif"%20alt="[/img]
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