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sudhir_g_thombare
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What is the Best Protection Device for Single Phase Motor

01/16/2013 12:35 PM

I have single phase pump in quantity for different applications. What is best protection to prevent the motor winding?

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lyn
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#1

Re: what is the best protection device for single phase motor from

01/16/2013 1:01 PM

Fuses? Thermal overload? Circuit breaker?

Depends.

The best thing for the motor is for you to gain an understanding of the various protection methods available.

Basic motor protection scheme - Electrical Installation Guide

[PDF]

Electric Motor Controls Tutorials - Process Control and Instrumentation
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redfred
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#2
In reply to #1

Re: what is the best protection device for single phase motor from

01/16/2013 1:55 PM

Yes! The best protection for any electrical system is a knowledgeable engineer designing the system.

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Fredski
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#3

Re: What is the Best Protection Device for Single Phase Motor

01/16/2013 2:23 PM

"best" is a subjective term, money is always an issue. fused line legs, circuit breakers, motor monitors thermal overloads, etc are all plentiful
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JPool
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#4

Re: What is the Best Protection Device for Single Phase Motor

01/16/2013 5:30 PM

The best protection is to unplug it.

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#5
In reply to #4

Re: What is the Best Protection Device for Single Phase Motor

01/16/2013 8:32 PM

Celibacy, in other words.

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sudhir_g_thombare
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#6
In reply to #4

Re: What is the Best Protection Device for Single Phase Motor

01/16/2013 11:29 PM

Thank you very much for your valuable reply.

But, Even if protection is costly, it should be protect enough. B'coz, cost will no matter when it will long last.

B'coz. Same thing was happened with unother system. I have distill water preparation plant. Where we have water heater to boil the water. Some times my electrician was switching on that plant but later on due to work load they got forgot to swtich OFF before water tank got empty. many times I was loosing the heaters.

So, I decided to put water level indicator with contactor logic. No more heater burning...! No more loss. But I was saving much heater cost which was covered the contactor logic cost...!

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#7

Re: What is the Best Protection Device for Single Phase Motor

01/17/2013 3:41 AM
  • Motor overload devices protect the motor.
  • Fuses protect the cables.

Slam dunk.

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#8

Re: What is the Best Protection Device for Single Phase Motor

01/17/2013 5:41 AM

Great question.

If I was trying to protect such motors I would select a circuit breaker that would trip if say 200% normal running current is taken for about 1.5 -2.5 seconds. When a motor is stalled for any reason, it usually takes starting current continually....

It must basically ignore the high starting current (usually 4-8 x running current) for say 1 second.

BUT, if you are using motors that are only just "man enough" for the load, the running up times may be too long to allow the times I have quoted.....you may need to find out how high and for how long your motor (connected to your load of course!) needs to start/run up and work from there.....

Some cheap breakers "creep", which is how we described the effect that after say 5 starts, the breaker trips, because at each start it is "creeping" mechanically towards tripping. Buy quality with a good guarantee.

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Sapper
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#9

Re: What is the Best Protection Device for Single Phase Motor

01/17/2013 11:19 PM

To prevent the motor winding...turn it off...

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Sapper

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sudhir_g_thombare
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#10
In reply to #9

Re: What is the Best Protection Device for Single Phase Motor

01/18/2013 11:09 AM

Dear,

What do you mean by turn it OFF...?

Don't you understand my problem, then please read my words once again...!

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lyn
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#11
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Re: What is the Best Protection Device for Single Phase Motor

01/18/2013 11:34 AM

The best protection for an electric motor is the method that makes the most sense for the SPECIFIC application and meets applicable local/national codes.

Your problem is that you do not understand this.

Take a course in electrical theory or hire an engineer, or electrician.
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sudhir_g_thombare
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#12
In reply to #11

Re: What is the Best Protection Device for Single Phase Motor

01/18/2013 12:00 PM

My Answer is for those poeple those who are saying ' turn it OFF '

Engineering is not stopping at running with problems.But it will stop at when we can sleep long.

We know that after turned OFF the pump on time, it will never ever burn. But, I want more than this. at any cost motor winding should not burn with normal load.!

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lyn
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#13
In reply to #12

Re: What is the Best Protection Device for Single Phase Motor

01/18/2013 12:25 PM

What we have here, is failure to communicate.

Motor windings do "not burn with normal load". Motor windings burn under abnormal loads.

That's what the protection is for.

Properly specified motors will last a long time.

Get some professional help.
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Users who posted comments:

Andy Germany (1); Fredski (1); JPool (1); lyn (3); PWSlack (1); redfred (1); Sapper (1); sudhir_g_thombare (3); Usbport (1)

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