Allen Bradley 709 runs when manually engaged only

I see from the picture you have a multi voltage ac coil in your AB contactor...it says 110 208 220 VAC.
One of your previous post mentioned tried pushing the contactor closed and got a horrible buzzing.
More than likely you were fighting the energized coil.
 
If the motor buzzes, only single phase power is being delivered.
The contactor contact tips are burned or missing , the overloads are faulty or you have a broken connection.
There is not much more other than the operator switch , incoming wire or associated wiring to cause the problem.

Did you test the overloads with an ohm meter? Did you test the contactor poles with an ohm meter? Wiring can be inspected and tested next. Are all 3 phases being delivered to the contractor?
 
Ulma Doctor said:
If the motor buzzes, only single phase power is being delivered.
The contactor contact tips are burned or missing , the overloads are faulty or you have a broken connection.
There is not much more other than the operator switch , incoming wire or associated wiring to cause the problem.

Did you test the overloads with an ohm meter? Did you test the contactor poles with an ohm meter? Wiring can be inspected and tested next. Are all 3 phases being delivered to the contractor?
Click to expand...
I decided to rehab the starter. The contacts were quite pitted and some were quite thin. I'm awaiting NOS parts from eBay (coil and bot sets of contacts) and will install and resume testing. The loud buzzing seemed to come from the starter itself.
 
When you disassemble the current starter take a look at the coils to see if there are places to install a jumper for 220V activation. I ran into a similar problem (starter coil buzzing) when I first tried to startup my Racine power hacksaw. As it turned out the coils were 440 volts. On 220 volts there was only enough power to get them to buzz, but not energize enough to pull in the contacts. I changed them out for 220V coils, and everything ran fine. I don't have tons of experience with 709 starters, but I've never seen multiple voltage coils before. They may be more common than I'm aware of since my experience is mainly with 220- and 440-volt industrial systems.
 
The A06 coil is a 220v so the new parts should solve your problem. Check that the coil slides in and out easily and the spring is functioning. I'd also order some new heaters and swap them out at the same time. Those old 709 will last your lifetime. It has been abused . Dave
 
You must log in or register to reply here.
Back
Top