hydraulic pump jammed

davelerave · May 19, 2010

hey

got called to a steel punching machine today

basically there's a 230v hydraulic pump connected to a couple of solenoid valves and pistons

when the pump is started it appears to be seized and trips the c20 at the board

afaik these pumps run continuous and the valves operate the rams?

there was a limit swich seized which i freed up.

anyone familiar with these offer advice thanks

Jonesy83 · May 19, 2010

worked on a few hydrolic pumps on dock levellers have you tested the motor on the pump

Blueblood · May 19, 2010

Have you checked out the motor. Is it the overload that is coming out or MCB. Are you sure that you are not trying to start it under load, due to an underlying fault. If the motor tests ok, the quickest way to prove motor is to split it from the pump then run it.
More info required to diagnose fault.

davelerave · May 19, 2010

no

i could separate the motor from the hydraulics i suppose

should it run free regardless of the valves open or closed- i think so?

there s as a small oil tank

davelerave · May 19, 2010

Blueblood said:
Have you checked out the motor. Is it the overload that is coming out or MCB. Are you sure that you are not trying to start it under load, due to an underlying fault. If the motor tests ok, the quickest way to prove motor is to split it from the pump then run it.
More info required to diagnose fault.

there's a manual starter in panel set at 25amp but the 20amp c type at board trips- final circuit must be undersized

i thought about separating them- no manual no drawing !!

but i figured the prob was on the pump/hydraulic side

netblindpaul · May 19, 2010

Dave,
First, check the FLC of the motor & reset the TM O/L correctly to that.
You are correct in assuming the pump should run, unless there is a hydraulic fault. We'll come back to that later.
I would suggest you decouple the pump & motor & try the motor on its own.
IF you disconnect hydraulic lines KEEP THEM CLEAN!
Contamination greater than the clearances in the hydraulic compnents can cause failure,
Please understand that most hydraulic directional control valves have no seals they rely on clever fluid dynamics to seal the ways.
Dirt is a killer.

IF the electrics run OK then you could have a mechanical or hydraulic problem.
Try turning the pump by hand it may be stiff but really it should turn.
Depends a lot on the pump, there are many kinds pump data would help.
IF the system is designed such that they pump runs at all times against a pressure relief valve then this could be jammed.

Where are you, if you need a good electro mechanical engineer to solve give me a shout, it's what I do most days!

I also teach hydraulics!

davelerave · May 20, 2010

i think the pump runs at all times

motor overload at lowest setting in panel-25amp

gonna ring supplier-don't wanna get into hyraulics

davelerave · May 21, 2010

netblindpaul said:
Dave,
First, check the FLC of the motor & reset the TM O/L correctly to that.
You are correct in assuming the pump should run, unless there is a hydraulic fault. We'll come back to that later.
I would suggest you decouple the pump & motor & try the motor on its own.
IF you disconnect hydraulic lines KEEP THEM CLEAN!
Contamination greater than the clearances in the hydraulic compnents can cause failure,
Please understand that most hydraulic directional control valves have no seals they rely on clever fluid dynamics to seal the ways.
Dirt is a killer.

IF the electrics run OK then you could have a mechanical or hydraulic problem.
Try turning the pump by hand it may be stiff but really it should turn.
Depends a lot on the pump, there are many kinds pump data would help.
IF the system is designed such that they pump runs at all times against a pressure relief valve then this could be jammed.

Where are you, if you need a good electro mechanical engineer to solve give me a shout, it's what I do most days!

I also teach hydraulics!