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Another Bridgeport power feed issue

seej

Plastic
Joined
Jan 29, 2020
Hey guys I have a head scratcher. I'm working with an old Bridgeport with the 6F. I'm not sure if it's an A B or C but it only has the rapid traverse and speed adjustment knob on the table. The rest of the guts are in a box on the base of the machine. A while ago it started to quit intermittently but would wake back up after a light rap with the hammer. It finally died. I've taken the motor apart and cleaned it out and replaced the brushes but now it only runs one direction. Both the micros work. According to the wiring diagram floating around everything is wired correctly. Somebody replaced the board once upon a time though and he mentioned he had to change some wiring. I can make the motor run both directions if I swap the field wires so it should be fine on that end. I'm wondering if something with the newer board changes where these wires are supposed to go. Where do I go from here?
 
Nope, wiring issue or switch. The only changes that should be made when updating to the 8F board is that the pot needs to be changed.

When you say both switches work, can you be a tiny bit more specific. When power is off, can you ohm the switches? In neutral, both switches should be in the normal state (COM to NO is open, COM to NC is closed). When you engage the handle in a direction, does the correlating switch turn on (COM to NO is closed, COM to NC is open)? How about the other switch? Dont test this just by pushing in the switches, do it with the actual handle and cam and checking the values on the paddles of the switch. It is possible that the switch isnt in the proper position and just needs to be adjusted.

Is your motor a 4 or 5 wire motor? If its a 4 wire motor, ensure that green is NOT going to ground, it is going to one of the reversing switches.

Jon
H&W Machine Repair
 
Thanks for getting back to me. Ok I've checked and everything is as it should be as far as normally open normally closed vs. handle position. I checked voltage with each switch on (handle engaged) and get 120v to one side (the side that works) and only about 40v to the other (when I switch the handle). If I switch all my wires I get the same thing, motor turns one way just opposite handle position. If I switch my white and green w/ tracer wires that go to the field the motor turns opposite direction. It is a 4 wire motor and my green is going to the green w/ tracer wire.
 
Is the motor turning the same way both times? IE no matter which way you turn the handle or have it wired, the motor only moves the table in the same direction?

Jon
H&W Machine Repair
 
Nope. If I wire it normal it turns one way, if I switch just the field wires it turns the other way.
 
Thanks for the help but no dice. I figure it has to be the board. I checked the individual wires and I'm confident-ish there aren't any breaks. They're all hooked up right. And I can make it run off of either switch so those should be fine too. Sent the board out lets hope they find something wrong with it haha.
 
What wiring diagram did you use to verify wiring?

I will be shocked if its the board, I have never seen the board be the issue when the unit will only run in one direction.

Jon
H&W Machine Repair
 
Got the board back today. Installed. All is well. Thanks for the attempts though.
 
According to Radwell they replaced a diode, a capacitor, and cleaned it. Oddly enough the rapid traverse also works now and that hasn't for several years according to the other shop guys haha.
 








 
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