Cause of frequent Pre Lubricating gear pump Cb tripping

[xaired]

Dear Gentlemen,

I am hoping that someone would share his experience to the problem that we are experiencing now. I have a lubricating pump with the following specs:

Pump Specification:
Rickmeier
Postfach 1340 D-58797 Balve

http://www.rickmeier.de

Made in Germany
R25/20 FL-Z-DB
350116-0 08/11
0011809501
R235006/423
Q = 27,5 / 33 l/min
n = 1395/1674 1/min
p = 2 bar

Motor Specifications:
Type: 5AP80 M-4
RTmax 600C
1395 min-1
Cos φ = 0,81
Th. Cl. F
380-420 Y, 1.95 Amps

The pump is working every 30 mins for 2 mins. Motor starter CB is set to 2.0 before but we put to max of 2.5amps. Gentlemen we have 10 units of this pump set only one is having a problem, we are experiencing frequent tripping of this unit. We replaced the CB already. Now we are considering the replacement of the pump. But i have doubt whether it is really a pump problem because it will trip once a day or sometimes not. When we monitor the current,it has a balance 3 phase reading of 1.9 amps per phase. once it trips when you restart it will work fine for several ours or even days.Its resistance is also 13.6 ohms per phase. We have not tried swapping of this unit to the others though.

We observe that it only trips during the starting. Gentlemen what do you think is the real cause of the tripping.. is there some problem inside of the pump mechanism? could anyone share his opinion please. thanks a lot..

 

[ScottyUK]

Is your motor controlled by a combination starter, i.e. a MCCB ('breaker') plus contactor and overload relay? Generally the MCCB is sized to protect against short circuit, and the overload relay provides thermal protction. If this is the case then the MCCB sounds too small.

If you're not sure what I'm talking about then post a picture of the starter components with enough detail to see settings and we'll take it from there.