HSCF water supply pump

[Krunal15]

We have hscf water pump having 75 kw rating. But when we start it takes more current than its full load current. What can be the reason of over current? AS We checked, pump is running free and no problem inside pump assembly. So what can be problem??

 

[LittleInch]

Errr that's what electric motors do. A figure of up to 6 times full load current is normal.

Your switchboard normally allows for a motor starter. What's your problem? Does it trip?

Is that what you mean?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[itsmoked]

What Voltage?
How is the power supplied, a utility or a generator?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[georgeverghese]

Startup high motor current can be reduced considerably by going for soft start or variable speed - ask the electrical engineer to help - soft start may be cheaper if you dont really need variable speed.

 

[Artisi]

Are you talking about initial start-up current or running current?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Krunal15]

We have soft starter panel of 90 kW. Pump takes over current in running mode after start mode.And even after over current, motor doesn't trip. I have not good knowledge of electrical side but want to know what can be the issue with this problem??

 

[Krunal15]

Voltage rating is 415V. And starter panel is LT panel.

 

[Artisi]

Is this a new or old problem?
A lot more application / history is required to even start guessing what the problem MIGHT be.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[LittleInch]

OK,

If we're going to be of any help here you need to give us a lot more data.

So please provide:
Pump curve
Motor data V, full load current, rated shaft power,
Actual flow and differential head the pump is working at
Actual voltage and current the motor is working at.

kW rating doesn't mean a lot - is this shaft power, max input electrical power? what?
How much more power is it taking?

Is it new or has something changed?

Usually you find out the pump is flowing faster and less efficiently than intended hence drawing more power than planned, but we need data above to try and see what is happening. The motor should be sized for end of curve operation, but sometimes it isn't

Occasionally the pump impellor(s) is not what was designed for.

At present we have about 5% of the required information.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

So the motor current in normal operation is >130amps approx., and it still doesnt trip. So you've got 2 problems, an electrical problem at the soft starter panel, and a pumping problem. In this pump forum, we may be able to help with the pumping problem, if you can provide more details.

 

[TenPenny]

The motor will draw as much current as it needs to power the pump.

If you overload a motor, it will draw more current until it overheats.

Normally, the electrical controls are configured with 'overloads' set to prevent this from happening.

If I understand correctly, you have two related problems: Your electrical controls do not have the overload protection properly configured. And, the pump is drawing too much power from the motor. Why is the pump drawing too much power? That could be many things. Was anything changed, in the pump, or in your system? Try throttling back to reduce your flow. Oftentimes, this will also reduce the power consumed. This may give you a pointer about what is going on.

But without knowing the system details, it's rather hard to come up with useful advice.