Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: dsesmg on July 06, 2009, 08:24:59 AM

Title: Motor ON/OFF
Post by: dsesmg on July 06, 2009, 08:24:59 AM: Hi, I am trying to turn on and off an induction motor(220VAC, 90W, 1.0A, 1550RPM/60Hz) by using a breaker and a magnet switch, and two switchs.
This is the circuit I came up with.
http://www.flickr.com/photos/34955071@N02/3694441534/#sizes/o/ (http://www.flickr.com/photos/34955071@N02/3694441534/#sizes/o/)
I tried this circuit. When I push ON switch, the magnet switch is engaged and when I push OFF switch, the magnet is disengaged. But, the problem is , the motor is not moving at all.
I checked the output(where the motor should be connected) voltage of the magnet switch and my tester shows 216VAC. If I connect the motor directly to the 220VAC main, the motor works perfectly.
But, when it is connected to magnet switch, it doesn't work.
Could you please advise me what is wrong?
Title: Re: Motor ON/OFF
Post by: dsesmg on July 06, 2009, 05:30:56 PM: somebody, please help me~
I am lost and desperate.
Title: Re: Motor ON/OFF
Post by: billhowl on July 06, 2009, 06:55:29 PM: You have label wrongly on the on/off switch, the connection look OK, you may check on the DC resistance between the L1 to T1 and L3 to T3 by manually press to close the contact.
Title: Re: Motor ON/OFF
Post by: Soeren on July 07, 2009, 06:44:27 AM: Hi,

Without knowing your relay (what you call a magnet switch), it's not possible to see if you wired it correctly or not, so please, either provide labels for every terminal on the relay or direct us to a datasheet of the relay.
At the very least, provide the make and model/type number of the relay.
Title: Re: Motor ON/OFF
Post by: dsesmg on July 07, 2009, 07:12:27 AM: Hi, I am sorry for my lack of explanation on the specification of my magnet switch.
I will try to find the information from the internet.
Meanwhile, could you refer to those pictures?
http://www.flickr.com/photos/34955071@N02/3697999936/# (http://www.flickr.com/photos/34955071@N02/3697999936/#)
http://www.flickr.com/photos/34955071@N02/3697191035/# (http://www.flickr.com/photos/34955071@N02/3697191035/#)
http://www.flickr.com/photos/34955071@N02/3697192203/# (http://www.flickr.com/photos/34955071@N02/3697192203/#)
Title: Re: Motor ON/OFF
Post by: billhowl on July 07, 2009, 07:24:43 AM: This is not relay, is Contractor which using low current switch to control high current device, it have low current coil to control the contact to close.

LG GMC-22 Contactor, 3 Pole META MEC Series
LS / LG GMC-22 Contactor, 3 Pole Meta-MEC series long life contactor with auxillary contact set.

http://www.partsfortechs.com/asapcart/gmc22-contactor-3-pole-meta-mec-series-p-86.html (http://www.partsfortechs.com/asapcart/gmc22-contactor-3-pole-meta-mec-series-p-86.html)
http://eng.lsis.biz/product/product/introduce/detail_info.asp?product_code=P00012 (http://eng.lsis.biz/product/product/introduce/detail_info.asp?product_code=P00012)
http://www.cheil-wiring.co.kr/new_cheil/eng/product/pdf_down.asp?dir=http://www.cheilelec.com/product/pdf/product5/&file_name=CMC%2022N.pdf (http://www.cheil-wiring.co.kr/new_cheil/eng/product/pdf_down.asp?dir=http://www.cheilelec.com/product/pdf/product5/&file_name=CMC%2022N.pdf)
Title: Re: Motor ON/OFF
Post by: Soeren on July 07, 2009, 08:17:40 AM: Hi,

A contactor IS a relay!
Title: Re: Motor ON/OFF
Post by: Soeren on July 07, 2009, 10:11:52 AM: Hi,

This should work, assuming the "no" terminals are shunted when energized.
(http://That.Homepage.dk/Img/RelayHold.jpg)
Title: Re: Motor ON/OFF
Post by: dsesmg on July 08, 2009, 04:41:47 AM: Quote from: Soeren on July 07, 2009, 10:11:52 AM
Hi,

This should work, assuming the "no" terminals are shunted when energized.
(http://That.Homepage.dk/Img/RelayHold.jpg)

Hi, I tried this circuit just few minutes ago. Stragenly it is not working.
I checked the output voltage of magnet switch and the voltage from the main outlet.
My tester shows 216VAC on both sides.
The motor works perfectly when it is connected directly to the outlet but not working when it is connected to the magnet switch.
Title: Re: Motor ON/OFF
Post by: Soeren on July 10, 2009, 03:31:20 AM: Hi,

Very odd! Did you try connecting a lamp in place of the motor?

If you can get a lamp of say 60..100W to light, try more lamps until you reach the equivalent draw of the motor.

Did you measure the voltage with the motor connected?

It may be bad contacts (too high resistance) in the relay, but if that's the case, it will show as a low(er) voltage with the motor connected.

EDIT:
Just strikes me (and got me to re-read your original post)... Considering it's an induction motor - is this really a mechanical contactor or could it be a solid state type? (i.e. does it "klonk" when energized/released?)
Title: Re: Motor ON/OFF
Post by: guru on July 11, 2009, 05:59:50 PM: Just to make sure, since you say this is a 220VAC motor, do you have a starter cap on the motor? Unlike DC motors AC ones need starter caps for the initial kick to get the started or they just kind of hummm. Under certain conditions they may still start but it would be unreliable. Probably not your problem, but just checking.

C