Connection of Dol Starter With Multimeter

[Engineer54]

Not unusual to want to monitor power of a motor, it provides better protection for the connected mechanical load than the motor overload. The mech load may well be damaged if jammed, by the time the motor overload has got around to tripping....essentially the power meter is acting as a shearpin.

You wont need separate CT's for such a small motor, the power monitor would be connected directly to the monitoring relays...have a look at uk.rs-online.com/web/p/monitoring-relays/0465258/ or similar. All this monitor would do is unlatch your starter circuit, not display the actual true power, although pricier ones do.

If you are wanting to display the motor current have a look at www.crompton-instruments.com/datasheets/Analogue_Instruments_REV_04-10.pdf some connected via CT's some directly connected.

A typical monitoring device only displays, what your talking about is a much more expensive protective device!! The OP has stated that it is only to check current and voltage, not very fine over current protection!!

 

[SheffSimon]

A typical monitoring device only displays, what your talking about is a much more expensive protective device!! The OP has stated that it is only to check current and voltage, not very fine over current protection!!

uk.rs-online.com/web/p/contactor-control-relay-overloads/7061005/ displays the current, protects the motor and mechanical load....£65. Used loads of these, combined with Siemens motor overload and contactor....job done.

 

[Engineer54]

Er, well why would he want one of these units, if all he wants is to check the current/voltage. But what your suggesting seems cheap enough!!

 

[Marvo]

Sorry if it's already been mentioned but you can also use a phase angle monitor to prevent overload, it's sometimes more accurate depending on the application.

 

[formach]

Thanks Sheefsimon for ur reply...

i got some additional question..can anyone here tell me what is that? (red circle in attached pic)


Thnk you for your time

 

[formach]

I'm a little confused as to why your asking these questions?? For a start why would you want to monitor such a small motor, What sort of monitoring unit are you connecting the CT's etc too. Whatever unit it is, surely it would come with a wiring diagram??
In other words WHAT are you trying to do, and maybe more importantly, for WHAT reason??

Not sure your stated CT ratio is going to register your motors 1A. lol!!

And still can't see your diagram, very fuzzy to say the least!!

Are u serious that the ct ratio cannot register my motor reading?
as mentioned above the rated current r just 1.1A
did u mean i can just connect the power meter to the wire without ct coil?
how about i use 10/1 ct coil? can it detect the reading?

 

[ackbarthestar]

Looks like Compton Instruments have the complete range for monitoring purposes. The smaller ones look as though they can be directly coupled . It now depends on whether they will go down to 1A.

 

[Engineer54]

Are u serious that the ct ratio cannot register my motor reading?
as mentioned above the rated current r just 1.1A
did u mean i can just connect the power meter to the wire without ct coil?
how about i use 10/1 ct coil? can it detect the reading?

You tell me. ....With a 60/5A CT, 60A through the coil will give an output of 5A. 1A through the coil will give you what??

 

[Knobhead]

Thanks Sheefsimon for ur reply...

i got some additional question..can anyone here tell me what is that? (red circle in attached pic)
View attachment 16626
Thnk you for your time

You say you have got this working?

 

[formach]

You say you have got this working?

this is another circuit act..i have to study about this circuit but i have no idea some of the component..
i thnk it is a contactor(-k1) and sensor(-m100)..