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3 phase for Bridgeport

And you can also hit stop and let it coast down to depth, then reverse. I did this all the time on machines fed with utility three phase. Felt like abuse to me to slam them from forward to reverse. It suffices to say that this (VFD being able to power tap) isn't really a problem to be worried about. A rotary converter is good too though.
 
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I don't ever do production or volume work but do power tap on occasion with my mill. I've always started the tap and powered it to the desired depth and then stop the motor. Then I reverse and back the tap out. I've never even broken a tap doing that operation.

I don't have one of the tapping units that reverses with a lever, but that might be a wise acquisition for production power tapping.

I avoid fast reversals, since if the motor is damaged, I'm the one who will have to replace it.

:rolleyes5:
 
I am just not sure what way would be the best way for him to go. I talked to Phoenix phase converters they said since the BP is over 30 years old we should go with a 3HP converter, they said the older motors weren’t as efficient as the newer ones. Comments welcome.
 
Put a VFD (Sensorless Vector Mode) with a dynamic braking resistor on it and don't look back. Power tapping is not an issue and you should vary the speed with a potentiometer. Extremely convenient and effective - did it for years till I went with the CNC. I used a toggle switch for forward/reverse and I just flipped the switch to reverse the tap while tapping. Worked great.

I paid around $375 for a 3hp single phase input WEG drive with a dynamic braking resistor for my lathe a couple of years ago. Works great but there are many drives out there that also fit the bill and some can be cheaper.

With the drive you get variable speed with the twist of the pot and dynamic braking - you don't get that with a converter and these are HUGE features. My Dad could not believe how fast my spindle would stop on my Bridgeport - think he was a bit jealous!
 
Mark could you please recommend a VFD link with all the parts we need. I am a bit over my head on the best way to go on this thanks.
 
Many manufacturers built their machines with zero speed switches or timers and utilized plug reversing for instant stopping of the spindle.
 
Mark could you please recommend a VFD link with all the parts we need. I am a bit over my head on the best way to go on this thanks.

This is the drive and price is probably pretty typical - for WEG you have to go to 3 hp to get the braking resistor which is not an issue:

CFW300B10P0B2DB20 | Weg | AC Drives

You need at least a 39 ohm resistor. I like this one - just bought one a week or two ago:

BR400W040 Delta Electronics/Industrial Automation | Motors, Solenoids, Driver Boards/Modules | DigiKey

You need a speed potentiometer to vary speed (knob not included - you need to look around but digikey will have them):

RV4NAYSD502A Precision Electronics Corporation | Potentiometers, Variable Resistors | DigiKey

As far as starting stopping, you may need to add a relay depending on how you would want to start/stop it. I would be happy to guide you through the setup and how do design the start/stop - just send me a PM. The instruction manual is not great but there is plenty of help available - I know the WEG folks extremely well.
 
I can't be sure but I think the motors on a BP is designed be reversed with the drum switch without problems to the motor. I had a friend that used a BP to drill and tap with a non reversing tapping head for years doing 100's of holes/day with the motor connected to supplied 3 phase from power lines. I have a Cincinnati ToolMaster and have been doing the same thing that is currently connected to 240VAC single phase using a Delta wound 3HP 1140RPM (1200RPM sync speed) 3 phase motor as a converter (RPC) with a non reversing torque limiting tapping head from SPI for quite a while (over 6 years) without problems, I completed tapping 3/8-24 on 400 pieces a few months ago and the same amount has been reordered, I'm tapping them now and told in a few months they will be ordered again. However my machine motor and my friends was original as supplied my the maker and probably designed to reverse. Years ago when I had my Big shop I made a reversing switch that reversed the wiring so reverse could be done with a foot switch and tapped thousands of holes without damaging the motor. I also know where my father worked they had a few BPs tapping by reversing the spindle, he worked there for 10 years, machines were there when he got there and were still running when he left!
 
Regarding the "didn't damage the motor" during 10 years of instant reversals - I think I'd be more concerned about the brutality the drive splines and associated gearing were exposed to. Motor is the last thing I'd worry about.
 
Regarding the "didn't damage the motor" during 10 years of instant reversals - I think I'd be more concerned about the brutality the drive splines and associated gearing were exposed to. Motor is the last thing I'd worry about.

That might be the fact when reversing lathe motors. From what I have seen the motors on BP and my Toolmaster are loosely coupled so that the magnetic coupling within the motor will not force instant reversal. Furthermore if you use the spindle brake, the breaking mechanism is on the motor side of the spindle spline so inertia will cause the spline to the side opposite the run side so that when starting the motor it will slap over to the other side, Vee belts and Variable speed belts will create the same effect. I notice that when starting my mill it winds up to speed, when reversing while tapping I notice the wind down then windup when spindle reverses. Also when using a RPC the weaker 3rd leg also loosens coupling so that motors when reversed using an RPC don't instantly reverse. I've had this ToolMaster for over 20 years, was used when I got it but was in excellent shape. It still is in excellent shape, I notice no issues with the splines and down feed gears are as good as they ever were.
 








 
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