High Current Indicator

[emzach]

Hi All,

I would like to ask for help for my project. My boss ask me to put an warning lamp when the load current reach 300A.

The condition:

-Crushing stone motor runs with unstable current (fluctuated).
-Fluctuating range (100A-250A) normal condition.
- Need to install indication warning lamp n buzzer when the load current reach 300A without stopping the motor (dont want the circuit breaker).

Really need some help here. Thanks.

 

[Richard Burns]

Use a current sensing relay with alarm outputs.
Possibly may need a brief time delay if the peak current may reach 300A for seconds without problems.
Output of the relay will supply the lamp and buzzer.
Assuming 3 phase motor and equal current in each phase choose the relay for the appropriate current on one phase.

 

[malcolmsanford]

Hi Rich I was looking at this thread earlier and was on the EATON site looking for CT sensors, bit noticed that the largest they do were 200amp

I noticed that the ones you linked to were also 200amp do they do a 300amp?

 

[Knobhead]

400/5 CT feeding a current relay with adjustable hysteresis setting. I got the relay from RS when I did exactly the same job. The CT was from D. K. Moriarty (honest!)

Sherlock Holmes

 

[Richard Burns]

Agree ^^^
Sorry Malcolm I was not looking into it in detail just giving the idea so the project could be planned; I can't readily find in the UK 300A current sensing relays however CT are available up to very high currents and so could be used to provide a reasonable output if the direct sensing is not available.

 

[Knobhead]

A 5VA 400/5A will do it nicely. Still got the drawing kicking about somewhere if the OP drops me a PM. I used the same system to control the infeed to a crusher.

 

[ackbarthestar]

You are going to have HV on the output unless they are all fully connected before you switch on....

 

[emzach]

Hi Tony,
I can't send PM to anyone yet. can you get me by email? emzach(underscore)edge(alias)yahoo(dot)com

 

[emzach]

Use a with alarm outputs.
Possibly may need a brief time delay if the peak current may reach 300A for seconds without problems.
Output of the relay will supply the lamp and buzzer.
Assuming 3 phase motor and equal current in each phase choose the relay for the appropriate current on one phase.

Thanks Richard. Helpful information.

 

[emzach]

bump for new info..