lukas86

Hey,

I'm a student going into electrical in BC, Canada.The mill I'm at has me looking at a problem. The situation is that when a log goes into the canter, and it gets jammed, the breaker trips and the PLC goes too. At the moment I do not have much information on anything else.

I was wondering that since the machine is getting jammed up, it draws more current, which causes the breaker to trip from this increase.

Shakey

The breaker trps to stop the motor burning out, it is going straight into an overload situation and the breaker is doing its job

lukas86

Thanks,

I was confident that was the case, but wanted to be sure.

rumrunner

I agree with shakey ,but i would also check that the motor is drawing the same current on all 3 phases and that the overload is set exact to the current on the data plate, also check for loose connections.
all the best with it

the folowing link may be usefull as well Welcome to www.wiringmanual.com

lukas86

I was told by my supervisor that all 3 phases are drawing the same current and the overload "should" be set exact to the current.

What I was told happens that when a log gets jammed in the canter, the breaker trips immediately. There is no delay of a few seconds before the breaker trips. I believe the breaker is 2000 Amps, and the current draw from the canter is close to that. To get over this tripped breaker situation, would it be safe to put in a slightly greater breaker size or will this burn out the motors too fast? I do not know the whole situation, but if a breakers job is to stop current flow when there's a problem, I don't want to tell my supervisor that this is the only option to fix this situation. I'm not sure if they can modify the intake to the canter either. I was wondering if anyone had any other ideas or options.

wayne

the overload isnt the problem ,its the size of your logs !
2000 amps thats a big log!

lukas86

The logs stay fairly constant size the whole time. This isn't a small saw mill I work at. The canter is fairly large and most of the equipment in this mill runs on breakers that are rated 1600/2000 Amps. There may be one or more pieces of equipment per breaker, but most of the larger pieces (ie. the canter) are on their own breakers.

tony.towa

I agree with the previous replies that have been posted. The breaker is doing its job in protecting the cables and motor. If a log jams the motor the increase in current is likely to be that quick that the breaker will trip out without a noticeable delay. If this is becoming a regular occurance check your motor running current under load and compare it with the manufacturers spec. If that is ok it sounds like the logs you are putting through are too big for the equipment. Mind you I do agree 200amps is one hell of a log!!!