Help with Allen Bradley 709 Magnetic Switch

J

jbaccell

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Hi,

This is my first post but I am a long time lurker. I am hoping through the colletive wisdom of the members I might get some guidance on the Allen Bradley 709 that is mounted to my Gemco Shaper. The shaper has a 3 phase 3 HP Baldor Motor that was originally wired for 480 volts. I rewired the motor to 240 and changed the "N" type heater coils to the proper size for the higher amps the motor will run at on 240 volt.

The intermittent problem I now experience is sometimes when I hit the start button, the motor jumps and the switch will smoke (not good I know). I have to jog the switch and then the motor will start and run properly. It almost seems like the coil is not strong enough to activate the switch. Sometimes, it works fine with no issue whatsoever. After initially experiencing the problem today, I kept turning the motor on and off throughout the day and it worked perfectly. Nothing is getting hot and the motor runs fine. Aside from any advice and guidance my question is am I suppose to change to coil in addition to the heaters I already changed?

I attached a photo of the switch including the coil. Making things even more challenging is the decal on the inside cover is oil soaked and almost impossible to read.

Thank you in advance for any and all comments, suggestions, guidance etc... I sure appreciate it as I am at a loss how to fix it.

Thank you.

Joe
 

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  • Allen Bradley 709.jpg
    Allen Bradley 709.jpg
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  • Allend Bradley Switch - Inside Cover.jpg
    Allend Bradley Switch - Inside Cover.jpg
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Last edited:
Yes, you need to change the coil as well as the heaters when changing operating voltage, some coils are dual voltage, some are not, that one is not. Some starters may use a reduced voltage transformer kicking down to 24 volt, obviously, that one is not. I had some equipment with starters from that era, could be as old as the 1930s or 40s.
 
Thanks so much for your help, I truly appreciate it. Would you know of any reference that I can use to figure out which coil I need?

Thanks again.

Joe
 
In a pinch, you could install a transformer to boost the voltage to the coil, but as old as the starter is, finding a suitable coil could be a problem, you may just want to replace the starter.
 
benmychree said:
In a pinch, you could install a transformer to boost the voltage to the coil, but as old as the starter is, finding a suitable coil could be a problem, you may just want to replace the starter.
Click to expand...
Thank you so much for taking the time to help, I do appreciate it.
 
benmychree said:
In a pinch, you could install a transformer to boost the voltage to the coil, but as old as the starter is, finding a suitable coil could be a problem, you may just want to replace the starter.
Click to expand...
John, would this work for me?In addition to the 3 Hp 3 phase motor, there is also a 240 volt 1/3 Hp motor for the rapid traverse that this would feed.

SQUARE D MAGNETIC MOTOR STARTER CONTROL 5HP 20AMP 208-230VOLT 3-PHASE FOR AIR COMPRESSOR MOTORS - - Amazon.com

SQUARE D MAGNETIC MOTOR STARTER CONTROL 5HP 20AMP 208-230VOLT 3-PHASE FOR AIR COMPRESSOR MOTORS - - Amazon.com
www.amazon.com

Again, my sincerest thanks for your help.

Joe
 
You should be able to find just the coil for a fraction of the price they're asking for the complete starter. I had to do the same thing when I bought a Racine power hacksaw. It has a 3 phase motor and was wired for 480 volts. I found the proper heaters and coil new on eBay for less than $50.00.

Here's a bulletin from Allen Bradley listing all the replacement parts for the 709 series starters. The coils are the first item on the first page. About the only thing you'll need to know is the size (00 thru 5). Then you can search using the part number provided.
 

Attachments

  • Allen Bradley 709 Renewal Parts.pdf
    1.4 MB · Views: 8
projectnut said:
You should be able to find just the coil for a fraction of the price they're asking for the complete starter. I had to do the same thing when I bought a Racine power hacksaw. It has a 3 phase motor and was wired for 480 volts. I found the proper heaters and coil new on eBay for less than $50.00.

Here's a bulletin from Allen Bradley listing all the replacement parts for the 709 series starters. The coils are the first item on the first page. About the only thing you'll need to know is the size (00 thru 5). Then you can search using the part number provided.
Click to expand...
Thanks very much for your help, I do appreciate it. I wil give it a try.

Thanks again,

Joe
 
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