# 120V motor feed and controls



## tim465 (Oct 24, 2011)

I am getting ready to wire up some controls on an existing 120V motor that feeds a conveyor. I want to add an on delay alert as well as emergency pull rope e-stops. A real simple circuit. I was wondering If I could use the same 120V circuit to feed my controls, which are rated 10 amps or less, and be able to run my motor which is a 1hp 120 V motor using a 30 amp rated solid state timing relay rated for 30 amps. Will there be a compromise on my lower rated controls in doing this? I was thinking I could wire my controls in parallel and that should be fine. What do you guys think?
Thanks,
Tim


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## 360max (Jun 10, 2011)

...so basically you want to tap off the motor feed to supply the control ckt with power?


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## Big John (May 23, 2010)

Without finding any code on it, logic tells me you want to limit the power through your control circuit to the value of your weakest component. If you have stuff that can't tolerate more than 10 amps, and you have 30A OCP then you need to tap in a fuse block or breaker rated at no more than 10 amps to power your control circuit.

It's done like that all the time.

-John


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## John Valdes (May 17, 2007)

Many combination starters use line voltage for everything. Some even come with transformers in them for the control circuit.
Certainly you can use the same circuit for the motor and for the control providing you have the capacity for both. Whats the timing relay for? And you say its rated for 30 amp? I do not think I can remember seeing a solid state timing relay rated for such high current.
I really have no idea of what you have or what you want to do.
Why not write it out and post it. What you have and what you want to do. The steps, one at a time. This way we can actually see the process in our mind before we start giving out any advice.


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## CanadianSparky (May 10, 2011)

John Valdes said:


> Whats the timing relay for?


The OP wants to wire in a on delay alert.


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## JRaef (Mar 23, 2009)

I too am not clear on what you want to do.

If you are asking if it is OK to use the control contacts that are rated for 10A to switch the 1/2HP 115V motor motor directly, then the answer would be no.

If, as the others interpreted, you want to use the same CIRCUIT to power your control devices and are wondering if the 30A breaker is OK for the devices rated at 10A max., then that's also no. This is what the others were addressing by suggesting you add another control circuit fuse rated 10A or less. You cannot safely protect devices rated at one level of current using a protection device that is rated for 3X that level. Even in the scenario that John Valdes mentioned, there would (should) be another control circuit fuse in there somewhere that is going to protect the 10A rated control devices.


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## tim465 (Oct 24, 2011)

Ok here is what the scenario is...
I have a about 40 feet of conveyor. I need to sound an alert before the conveyor starts. So I assuming I will need a timing circuit with and on delay. The conveyor is 120V 1 hp motor on a 20 amp circuit. I just want to use the same circuit to do everything (time delay circuit as well as fire horn, and then feed motor). What is the best possible way to do this? Also I will be wiring in rope pull stops, one on each side of the conveyor.
Thanks,
Tim


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## tim465 (Oct 24, 2011)

I am using a class 9050 Type FT-12 timing relay. It states it is rated for 3600VA on make and 360VA on break. I know my weakest link are my emergency pull stops. So what is my best way to protect the circuit and use this timing relay? I having a mocked up version of it wired and it works correctly. I guess my only concern is melting contacts either on this relay or on the e-stops. It just seems to me to use a motor starter for a single phase 120volt motor is overkill. The nameplate rating on the motor is 12.8 amps. 
Thanks for any direction!
Tim


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## tim465 (Oct 24, 2011)

I am wanting to wire a 5 second alert before conveyor start as well as put pull rope e- stops on both sides. I am wanting to use this square d 9050 ft-12 timing relay. It states its rated 120v and 3600va on make and 360va on break. It seems like its is capable of handling my 1hp mtr nameplate Amps 12.7 at 120v. Not sure what it means by make 3600 and break 360 va, please enlighten me. I have this relay wired up to simulate what I need and it works. I have take the initiated contact to feed my motor and horn. Does this sound right? The only thing I am worried about is melting the contacts in my e-stops (weakest link), but I could put a in line fuse on those. If you guys have a better idea please let me know. I am open for any suggestions!
Thanks,
Tim


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