# August 1949 Motor Circuit



## sparkiez (Aug 1, 2015)

So we went to check out a motor circuit on a basketball goal. Given that the motor and control box were in a very difficult and awkward position to try and troubleshoot, we just decided to pull it down. It is pretty cool, but I'm a bit hung up on the motor circuit. I have not worked with many single phase motors, and had a hard time finding as schematic for the windings and control circuit.

There are 4x wires coming into the box. Black, White, Red, Blue. Black is constant hot, white is neutral and Red/Blue are coming from a 3 position maintain toggle switch with the same hot as a common. There is also a very cool mechanical rotary limit connected to the shaft to open the circuit after a certain amount of rotation. This is the first time I've ever seen anything like that.

Posting here in part, because its pretty cool, but also to get a bit of help understanding the operation of this circuit. I see the definite purpose contactors are reversing the T5 and T8. The breaker is tripping as soon as we turn it on, without the motor connected, indicating a short. Before the short, the bottom contactor would turn on, but the top one would not.

Also, we are replacing this motor with a newer model. The name plate has the same specs, but the leads are not numbered, they are colored (sorry I don't have a pic of the new nameplate). They also seem to be configured the same way, so we just matched up the lead numbers on the old motor to their respective colors. I'm hoping to get a bit of help on this one, as we have to get it up pretty quick and I want to make darn sure we get it right before we reinstall it.


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## Wirenuting (Sep 12, 2010)

This is not a single phase motor.


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## frenchelectrican (Mar 15, 2007)

I dont know how ya got the three phase motor posted in the photo but if you have single phase source then therefore ya need single phase motor.

Let me posted the color to the number 

1 - Blue 
2 - White
3 - Orange
4 - Yellow
5 - Black
6 - NCA ( no color assigned )
7 - NCA
8 - Red 

( per NEMA setting the IEC is diffrent )

Please note the NCA may have different format so please double check the nameplate for latest info or check the motor manufacter to look up on the details. 

But typically most single phase motor to change rotation just swap 5 & 8 

If need more info just let us know we will try post the other info if possible.


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## Cow (Jan 16, 2008)

Wirenuting said:


> This is not a single phase motor.


We all have our days. I hate when I overlook the obvious!!


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## sparkiez (Aug 1, 2015)

Sorry about that. Here is the correct motor. Anyone know any good resources for single phase motors with start caps and start/run caps. I don't want to get caught with my pants down on a single phase motor control circuit like this again.

The first motor I posted was from a motor at the same site we were asked to look at while we were there.


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## Wirenuting (Sep 12, 2010)

I’m not sure what your question is. 
But with just the motor disconnected and no ability to reverse I would look at the micro switches. They wear out after so many cycles. 
If it microswitches worked and the motor only was tripping the breaker because it was cooked, see if a contactor had welded contacts. 

Did I answer this right? Hackwork has me 1/2 blind after giving him the Paczki.


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## splatz (May 23, 2015)

I can't tell from the photo, what's driving the gear with the limit switches?


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## joebanana (Dec 21, 2010)

When I encounter this type of situation, I draw the circuit out on paper, if there's no schematic, and usually during that process the "problem" becomes apparent.


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## John Valdes (May 17, 2007)

The motor came from Grainger.
Why not build a new control panel? Use an inexpensive three phase motor as well.

I bet an electric gate opener drawing is all you need to help you get started.
They are very similar.
But draw your own and put away the gate drawing asap.

BTW. Whats wrong with this existing setup? Motor bad?


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## John Valdes (May 17, 2007)

splatz said:


> I can't tell from the photo, what's driving the gear with the limit switches?


Its a travel limit switch. Likely two switches with adjustable cam on travel rod. Its most likely to raise the goal and to lay the goal down. Same as with an electric gate opener.


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## splatz (May 23, 2015)

John Valdes said:


> Its a travel limit switch. Likely two switches with adjustable cam on travel rod. Its most likely to raise the goal and to lay the goal down. Same as with an electric gate opener.


How is that gear turned by the motor shaft?


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## frenchelectrican (Mar 15, 2007)

splatz said:


> How is that gear turned by the motor shaft?


I think it work right off from the worm gear shaft or motor shaft if it was reduced speed by specfic X ratios. 

Basically simuair to the garage door opener system using currently.


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## splatz (May 23, 2015)

OK I couldn't make out the worm drive, I can see the corkscrew now. 

I have set those limit switches when they're right on the motor output drive but not something like this where you need gearing.


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## sparkiez (Aug 1, 2015)

Sorry, in class at the moment. I'm having a hard time finding the appropriate motor schematic. I'm wanting to see how these windings and internal components are cook figured. 

The other thing i realized is that I'm going to have to set the over travel limit back to the proper position when i reinstall the control box.


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## MechanicalDVR (Dec 29, 2007)

sparkiez said:


> Sorry about that. Here is the correct motor. Anyone know any good resources for single phase motors with start caps and start/run caps. I don't want to get caught with my pants down on a single phase motor control circuit like this again.
> 
> The first motor I posted was from a motor at the same site we were asked to look at while we were there.


I was just going to say that a 5hp 3ph motor on a basketball goal would really be out of place.

1/3 hp is pretty standard.


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## MechanicalDVR (Dec 29, 2007)

sparkiez said:


> Sorry, in class at the moment. I'm having a hard time finding the appropriate motor schematic. I'm wanting to see how these windings and internal components are cook figured.
> 
> The other thing i realized is that I'm going to have to set the over travel limit back to the proper position when i reinstall the control box.


The motor is from Grainger they should be able to tell you anything about it in a heart beat.


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## sparkiez (Aug 1, 2015)

MechanicalDVR said:


> I was just going to say that a 5hp 3ph motor on a basketball goal would really be out of place.
> 
> 1/3 hp is pretty standard.


Yea, my bad. I'm just a bit confused. What I'm seeing on those contactors is telling me that T5 and T8 are being swapped, but what I'm being told is that you only need to hook up T5 or T8 to start the motor. I thought they had to have their places swapped, not just hook up one or the other.


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## tates1882 (Sep 3, 2010)

sparkiez said:


> MechanicalDVR said:
> 
> 
> > I was just going to say that a 5hp 3ph motor on a basketball goal would really be out of place.
> ...


 nah they swap and both need connected to either series or parallel the windings depending on the voltage. If the breaker trips prior to moving the toggle control then the short is in the control circuit from breaker to toggle control or from breaker to the contactor the constant hot wire is landed on. Welded contacts would allow direct phase to neutral short from black wire terminal one to the neutral terminal on the second contactor.


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## just the cowboy (Sep 4, 2013)

Don't trust hook up. If someone else worked on it at some point then gave up it may not be hooked up correct and that is why it trips. 

They are just changing the winding for rotation.


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## micromind (Aug 11, 2007)

That motor was actually manufactured by the Doerr Electric Company and sold under the Grainger brand. Oddly, there was a certain span of years when every part of a Doerr, Emerson and Dayton motor was interchangeable, except the nameplate. They were all made by Doerr. 

To answer the question though, the rotation of this motor is changed by swapping T5 and T8. This changes the phase relationship of the start winding to the run windings. 

A fairly common way to do this is to have 2 contactors that are interlocked so only one can be closed at a time. 

For this post, I'll use only T3, T4, T5 and T8, ignoring the other leads. T3 and T4 are a run winding, T5 and T8 are the start winding.

For one direction, one contactor connect T3 to T5 and T4 to T8. This will result in clockwise rotation when looking at the back of the motor. 

For the other direction, the other contactor connects T3 to T8 and T4 to T5. This will result in counter-clockwise rotation. 

There are other ways to do this (a 2 pole double throw contactor comes to mind) but this is the most common one I've seen.


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## John Valdes (May 17, 2007)

splatz said:


> How is that gear turned by the motor shaft?


Some are connected by a small chain and two sprockets.



sparkiez said:


> Yea, my bad. I'm just a bit confused. What I'm seeing on those contactors is telling me that T5 and T8 are being swapped, but what I'm being told is that you only need to hook up T5 or T8 to start the motor. I thought they had to have their places swapped, not just hook up one or the other.


T5 and T8 are swapped for direction. You still need to connect it to run.
The two leads sticking out are for the capacitor.
There are more wires to consider.

Check out these drawings. Single phase starts on page 8. This is all you need to reconnect the motor. 
http://www.goevans.com/filesSite/EHB_pgs0803.pdf

FIY. Just because this is a Dayton motor, does not mean you must replace it with a Dayton.
All you gotta do is find the same specs on any brand. Making sure RPM, voltage and frame match.

Looking at the picture again, it seems the control panel is in very good shape. I would just reuse it. Check it out and reuse it.


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## sparkiez (Aug 1, 2015)

So we went back out there and got it all set back up. The relays contacts were in pretty bad shape in the control panel (lots of carbon markings and welds). Pretty sure I blew out one of the coils too. I should have known better than to press one in on a reversing circuit. You know, I didn't even think to check my Ugly's book for the winding configuration :crying:

We ended up using the overtravel limit and rebuilding the starting circuit. I also took a look at that PDF you sent and saved it on my phone for future reference. I realized that until now, I've never had to work on a single phase motor. It has always been three-phase motors! :vs_laugh:

So all-in-all, we got it back up, and I learned a few things, and also got a great reminder to take my time and troubleshoot, regardless of the time limit. Anywho, thanks for all the help, once again!


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## John Valdes (May 17, 2007)

sparkiez said:


> I should have known better than to press one in on a reversing circuit. You know, I didn't even think to check my Ugly's book for the winding configuration :crying:


Just a heads up.
Never and I mean NEVER press a contactor in, to close the motor circuit!
I remember a guy that did it and it blew up in his face.
The motor was shorted out and by pushing in the contactor, he got the dead short in his face..

Here's what I learned to do.
Apply control voltage only (if possible) and test operation without line/motor voltage. Once you are happy with the operation, reintroduce the power/motor voltage.
In your instance, you would just remove the motor conductors from their terminals and then test the operation of the reversing contactor and limit switches.
You will always need to tune/adjust the travel again if you should apply power to the panel without the load connected.
This must be done with the goal post motor connected.


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## MechanicalDVR (Dec 29, 2007)

John Valdes said:


> Just a heads up.
> Never and I mean *NEVER press a contactor in*, to close the motor circuit!
> I remember a guy that did it and it blew up in his face.
> The motor was shorted out and by pushing in the contactor, he got the dead short in his face..
> ...



Good advice but it's rarely if ever followed.


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