Thread: magnetic switch
View Single Post
  #2   Report Post  
Posted to
Josepi[_19_] Josepi[_19_] is offline
external usenet poster
Posts: 180
Default magnetic switch

The O/L settings are usually determined by a chart that comes with the
starter or O/L sensing units based on the size of the motor it needs to run.

I am not familiar with this particular model but the dial settings are most
likely multiples of the basic O/L unit's current allowance, at least in
thermal units, anyway.

In thermal units the best cure, usually is to replace the heater coil as the
units can degrade with repetitive usage, as in a power tool.

I would get somebody with a clamp-on ammeter tester and some knowledge and
try to determine if the running current for the motor and the startup
current seems reasonable. The O/L tripping out indicates it is not. Motor
repair places should be able to test and verify the motor is fine and even
check the settings on the O/L. They do get weak after years of usage,

Check the motor for leakage to ground with a simple ohmmeter or HV Meggar
meter (better). If the unit pops on starting then the starting contacts or
starting capacitor may be done on the motor. Windings do not typically go
bad without a massive burning smell or indication. Contatcs and capacitors
do. De[ending on the type of motor it could have a running capacitor
installed. This would be the usual suspect and easy to replace. (make sure
you discharge the beast before touching - get help with this one! A line
charged capacitor can set you on your ass and they can hurt badly)

Short of any technical help start by cleaning inside and then replacing the
cheapest parts...O/L on the contactor, contactor and then the motor. Best
to get somebody with a meter and some logic knowledge to keep costs down and
wasted money.

"John Grossbohlin" wrote in message

On a 3 HP Jet cabinet saw. The switch shuts off randomly while the saw is in
use. There appear to be adjustments in the switch but what do they do and
how does one judge the settings?