Hydraulic motor tripping contactor

Anyone know why a hydraulic motor would be tripping contactor?

Bad motor?

the motor may have a dual pressure vent
so it is only with a slight difference moving
"Auslöseschutz" German
most cases crane hydraulik use that like terrex or bigblue

andypugh wrote:

bevins wrote:

Anyone know why a hydraulic motor would be tripping contactor?

Contactor or RCBO?

A hydraulic motor doesn't have a contactor. Do you mean the electric motor on a hydraulic pump? Or are you talking about some sort of hydraulic overload?

if you are actually talking about an electric motor, not a hydraulic motor, then a contactor can't trip, they just don't do that. But contactors often have purely thermal breakers in the control circuit. Those are typically right for the job, though, so if they trip then the motor might have lost a phase, for example.

But first we need to know if you are talking about a hydraulic motor or an electric motor.

Hyraulic motor on the hydraulic pump that does my tool changer and tool clamp. The hydraulic motor comes on during power up, and stays on. Sometimes that little grey piece pops out. I think its arcing??? anyway this removes the three phase power to the motor.

Ok, That is the motor overload relay interrupting the power to the contactor coil. These are not instantaneous devises so the fault is a persistent one. The fault may be a hydraulic one (electric motor load is too great). The fault may be an electric one, motor failing. First check all wire connections, a loose connections can cause this problem. Check the actual electric motor running current with a clamp on current meter. Is the load for each phase equal? Do the results agree with the set point on the MOL? Now things get a little harder. Do you have a way to check the actual hydraulic load on the motor? This requires measuring both the pressure and the flow, not really easy unless you are setup to do it. The last thing is that the MOL may be bad or have a bad connection inside, some MOLs have "heater elements" that are sensitive to the motor current and if the connections are bad can cause a malfunction of the MOL. It is not unknown that the contactor may have a burned set of contacts that can make the MOL think there is a motor fault.

If you don't know what you are doing or don't understand please call an industrial electrician before anyone gets hurt or there is property damage.

John

this seams not to be a newer one more stable
you shoudt change that to new standards
on amazon and ebay ther are at about 15USD
even used siemens style ones

andypugh wrote:

Does the hydraulic pump spin when it should?

It doesn't do it all the time. Now it is going on two days and it is ok. It only does it when power on the machine.
It never did this before. when it does it, I can just reset it and it goes ok when running.

loose or broken wirer as of many movements are often to cause this unexpected problem

and as you say not everytime it can also be the oil thickness that leves to this
is the hydraulik oil filterd within the circle
CLEAN it filter and oil
using nylon Socks and GASoline