Grain Bin Motor Switches - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


Like Tree20Likes
Reply
 
Thread Tools Display Modes
Old 08-29-2019, 12:34 PM   #1
Junior Member
 
Join Date: Aug 2019
Location: North Carolina
Posts: 4
Rewards Points: 8
Default Grain Bin Motor Switches

I don't really work with motors, so forgive any ignorance below...

I am working on a grain bin for a family member and there are two grain augers that I need to supply. I planned to run a 100A circuit to a subpanel near the augers with a 2P 50A breaker for each motor. I want to have a switch to control the motors (preferably at the same time, since they need to be turned on in order or simultaneously, but it can be separate).

The two motors are identical 7.5HP, 230V single phase, (Nameplate says 36A) with built-in overload protection. We don't want to use breakers as the switch.

What would you guys use as an on/off switch option? I'm having a hard time coming up with an inexpensive single phase switch for that HP motor. Is there an option for one switch to run both? (Of course, outdoor application, needs to be enclosed from grain dust, rain, etc.)

Thanks for any advice!
jds777 is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 08-29-2019, 12:43 PM   #2
zap
 
tates1882's Avatar
 
Join Date: Sep 2010
Location: northwest
Posts: 1,301
Rewards Points: 1,042
Default

Quote:
Originally Posted by jds777 View Post
I don't really work with motors, so forgive any ignorance below...

I am working on a grain bin for a family member and there are two grain augers that I need to supply. I planned to run a 100A circuit to a subpanel near the augers with a 2P 50A breaker for each motor. I want to have a switch to control the motors (preferably at the same time, since they need to be turned on in order or simultaneously, but it can be separate).

The two motors are identical 7.5HP, 230V single phase, (Nameplate says 36A) with built-in overload protection. We don't want to use breakers as the switch.

What would you guys use as an on/off switch option? I'm having a hard time coming up with an inexpensive single phase switch for that HP motor. Is there an option for one switch to run both? (Of course, outdoor application, needs to be enclosed from grain dust, rain, etc.)

Thanks for any advice!
You need a mag and a few other goodies. I get the impression you're not an electrician and should be asking this question on a DIY site not a professional forum.
tates1882 is offline   Reply With Quote
Old 08-29-2019, 12:53 PM   #3
Junior Member
 
Join Date: Aug 2019
Location: North Carolina
Posts: 4
Rewards Points: 8
Default

Quote:
Originally Posted by tates1882 View Post
You need a mag and a few other goodies. I get the impression you're not an electrician and should be asking this question on a DIY site not a professional forum.
Thanks. I am a licensed electrician, but I don't practice anymore, and like I said, I don't know much about motors.
jds777 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-29-2019, 01:00 PM   #4
zap
 
tates1882's Avatar
 
Join Date: Sep 2010
Location: northwest
Posts: 1,301
Rewards Points: 1,042
Default

Quote:
Originally Posted by jds777 View Post
Thanks. I am a licensed electrician, but I don't practice anymore, and like I said, I don't know much about motors.
Keep in mind you have a dust ignition hazard also to contend with, look into a "pump" panel, most wholesalers will stock these. You can piggy back the start stop so both mags close together. Also fill out your profile, welcome.
tates1882 is offline   Reply With Quote
Old 08-29-2019, 01:07 PM   #5
Senior Member
 
Join Date: May 2015
Location: Sacramento, California
Posts: 14,053
Rewards Points: 26,352
Default

I've owned such motors -- and not one of them had O/L integral to their design.

I think you are entirely mistaken on this point. You want heaters in your contactor.
tates1882 and circuitman1 like this.
telsa is offline   Reply With Quote
Old 08-29-2019, 01:09 PM   #6
Senior Member
 
Join Date: May 2015
Location: Sacramento, California
Posts: 14,053
Rewards Points: 26,352
Default

Integral O/L are common for FRACTIONAL horsepower motors -- not for these beasts.

I know of no device that could easily be stuck inside them. ( Klixons won't do. )
Navyguy and circuitman1 like this.
telsa is offline   Reply With Quote
Old 08-29-2019, 01:17 PM   #7
zap
 
tates1882's Avatar
 
Join Date: Sep 2010
Location: northwest
Posts: 1,301
Rewards Points: 1,042
Default

Quote:
Originally Posted by telsa View Post
I've owned such motors -- and not one of them had O/L integral to their design.

I think you are entirely mistaken on this point. You want heaters in your contactor.
Exactly what I thought, why I recommended pump panels.
circuitman1 and telsa like this.
tates1882 is offline   Reply With Quote
Old 08-29-2019, 01:26 PM   #8
Junior Member
 
Join Date: Aug 2019
Location: North Carolina
Posts: 4
Rewards Points: 8
Default

Thanks for the suggestion on the pump panel, I will research. (And fill out profile)

It won't let me hyperlink to motor since I have less than 20 posts...

Teco-Westinghouse Farm Duty Single Phase TEFC Motor S7/54

It has a manual overload reset on it and the spec sheet includes it.
jds777 is offline   Reply With Quote
Old 08-29-2019, 02:25 PM   #9
Senior Member
 
joe-nwt's Avatar
 
Join Date: Mar 2019
Location: Canada
Posts: 386
Rewards Points: 776
Default

Not sure what your definition of inexpensive is and how close to the dusty environment you will mount it but here is a starting point for your search:

https://www.hubbell.com/hubbell/en/P...302D/p/1545467
jds777 likes this.
joe-nwt is offline   Reply With Quote
Old 08-29-2019, 02:43 PM   #10
Senior Member
 
460 Delta's Avatar
 
Join Date: May 2018
Location: Southern Ohio
Posts: 849
Rewards Points: 1,044
Default

Integral protected motors exist. Bottom pic is Klixon overload.
Attached Thumbnails
Grain Bin Motor Switches-6ca65731-ccf2-41ce-81d7-ed40d31a6b66_1567100524762.jpg  

Grain Bin Motor Switches-d4934c7a-7b99-4dc4-bbab-404fa415ed1c_1567100539986.jpg  

circuitman1 and jds777 like this.
__________________
Perfection is the enemy of good enough
460 Delta is offline   Reply With Quote
The Following User Says Thank You to 460 Delta For This Useful Post:
telsa (08-29-2019)
Old 08-29-2019, 03:58 PM   #11
Junior Member
 
Join Date: Aug 2019
Location: North Carolina
Posts: 4
Rewards Points: 8
Default

Have a Baldor motor almost identical to that one, but it's in a different location and has it's own control that a manufacturer added.

joe-nwt, that looks perfect, it doesn't switch both at the same time, but I think it would work. Thanks!
jds777 is offline   Reply With Quote
Old 08-29-2019, 06:29 PM   #12
Senior Member
 
Join Date: Oct 2016
Location: PA
Posts: 267
Rewards Points: 536
Default

You could use a 4 pole contactor, 2 legs for each motor.
John M. is offline   Reply With Quote
Old 08-29-2019, 07:08 PM   #13
Member
 
Join Date: Aug 2019
Posts: 81
Rewards Points: 162
Default John R retired electrician from Fed Gov

I agree, Mag starters with overloads. Also I not sure that a 50A breaker will be able to start a 7.5 HP SP motor. My SD cheat card says a 80A is required for a 7.5 HP. Most SP motor of that size do have overload already. I do not like them but they are better than nothing.
John R is offline   Reply With Quote
Old 08-29-2019, 11:22 PM   #14
Senior Member
 
Galt's Avatar
 
Join Date: Sep 2013
Location: Wis.
Posts: 596
Rewards Points: 1,037
Default

There are thousands of silo unloaders in the dairy state started with a 50 or 60 amp breaker most are capacitor start motors.
Galt is offline   Reply With Quote
Old 08-29-2019, 11:25 PM   #15
Senior Member
 
Galt's Avatar
 
Join Date: Sep 2013
Location: Wis.
Posts: 596
Rewards Points: 1,037
Default

I would try to avoid starting them both at the same time if it isn't necessary.
John Valdes and micromind like this.
Galt is offline   Reply With Quote
Old 08-29-2019, 11:31 PM   #16
Cow
Senior Member
 
Join Date: Jan 2008
Location: Eastern Oregon
Posts: 2,937
Rewards Points: 4,710
Default

Quote:
Originally Posted by telsa View Post
I've owned such motors -- and not one of them had O/L integral to their design.

I think you are entirely mistaken on this point. You want heaters in your contactor.
Quote:
Originally Posted by telsa View Post
Integral O/L are common for FRACTIONAL horsepower motors -- not for these beasts.

I know of no device that could easily be stuck inside them. ( Klixons won't do. )
Telsa,

Sometimes I think you're stuck in a bubble.

They do put thermal overloads in single phase motors every day of the week. I see them at work, my folks have one in a 7.5HP 230v single phase vacuum pump for a milking parlor.

The fact you tell people they are mistaken, when YOU just don't know, is baffling to me.

Please stop googling your answers just so you can respond to posts and act like the authority on all things electrical. It does get old.

To answer the OP's question, we'd most likely use pump panels.

The pump panels we use regularly are all 3 phase, so it takes a pretty good sized 3 phase pump panel to run a 7.5HP single phase motor. Probably a size 3.
Funksparky likes this.
Cow is online now   Reply With Quote
Old 08-29-2019, 11:34 PM   #17
Senior Member
 
JRaef's Avatar
 
Join Date: Mar 2009
Location: SF Bay Area, California
Posts: 5,136
Rewards Points: 2,152
Default

Farm Duty motors usually have thermal OL protection built-in, that's one of the things that make them different.


So you don't really need the OL relays in a starter. It's just that a Pump Panel is a known inexpensive way to buy an outdoor rated motor controller. Each one will have a Fused Disconnect or Circuit breaker, properly sized for the circuit, a contactor, an overload relay, an H-O-A switch and a Start-Stop Push Button (some use an H-O-A-Start switch, no PB). that gives you everything you need to make this work, all you would do is tie the Start circuit together so that starting one starts the other one at the same time.


You will need a NEMA Size 2 Pump Panels for 7-1/2HP 230V single phase motors. You will need one for each motor because if you combined them to try to use one Size 3 PP, the SCPD in the controller would be too large of one motor. Each Pump Panel will be rated for 45A, so you will need a 90A circuit to feed them.
__________________
"If you don't know where you're going, then any direction will do." -- Lewis Carroll
JRaef is online now   Reply With Quote
Old 08-29-2019, 11:35 PM   #18
Senior Member
 
Join Date: Apr 2013
Location: rural mn
Posts: 387
Rewards Points: 782
Default

Use a nonfused 60 amp 3r knife switch. This is a farm, dust tight is not required and has never been a problem outdoors. a Sq D standard duty sw # DU322RB is 10 hp rated. I agree that contactors are a best practice for controlling but they are not required. The farm world is a very different beast than the industrial world. Most farmers will have a heart attack when you try to sell them a pump panel to start and stop a motor that does not need automatic or remote control.
John R likes this.
tmessner is offline   Reply With Quote
Old 08-30-2019, 10:12 AM   #19
Senior Member
 
Join Date: Oct 2016
Location: PA
Posts: 267
Rewards Points: 536
Default

Quote:
Originally Posted by tmessner View Post
Use a nonfused 60 amp 3r knife switch. This is a farm, dust tight is not required and has never been a problem outdoors. a Sq D standard duty sw # DU322RB is 10 hp rated. I agree that contactors are a best practice for controlling but they are not required. The farm world is a very different beast than the industrial world. Most farmers will have a heart attack when you try to sell them a pump panel to start and stop a motor that does not need automatic or remote control.
Do not do this. Starting a motor this big with a knife switch will ruin the knife switch. You will have a lot a arcing every time you start or stop the motor
John M. is offline   Reply With Quote
Old 08-30-2019, 12:30 PM   #20
Senior Member
 
Join Date: Apr 2013
Location: rural mn
Posts: 387
Rewards Points: 782
Default

you are right. but these guys have been controlling silo unloaders for many many years 2 times a day this way. Starting and stopping under almost full load. Dirty wet corrosive silage. I have seen enclosures almost gone and the switch still works. Dangerous yes. We fix them when we see them.
tmessner is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:11 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com