# Brake motor failure.



## dronai (Apr 11, 2011)

What kind of plant is that ?


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## nolabama (Oct 3, 2007)

Swingspan drawbridge. We had the other motors transmission fail two weeks ago and the repairs had to be made to this side. We have a tug boat opening it for the time being.


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## jmsmith (Sep 10, 2011)

Am at a loss as to a vfd for the brakes. I was in on a similar setup on a railroad span in Amelia, LA. We had to provide separate 480V to the brakes thru two MCC contactors. These were activated via PLC control that also had over travel limits set. If there was a brake failure (fail close) for any reason, you could not open the span, or it would throw the span into "creep mode", in which case it would be moving at an ultra-slow speed until reaching full open or full closed. This is enough to keep from taking out your gearboxes or that ring gear..... They are a PITA to replace!!

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## nolabama (Oct 3, 2007)

The first setup the brakes ran off the motor's VFD causing a failure. The current setup the brakes have their own VFD in order to convert the single phase supply to three phase. This bridge is very remote and only has a single phase HV feed. Its all they could justify. All of our motors are standard for supply reasons....so we make the three phase with the VFD. So when the guys said that VFDs kill brakes I had to grab these photos today.


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## Big John (May 23, 2010)

Could you give a bit more detail about each picture? Sounds interesting, but I'm not sure what I'm looking at.

-John


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## nolabama (Oct 3, 2007)

I am. Give me a second to get the 'puter hooked up to the interwebs. I hqve a couple of other pics from this bridge. Its quicly becoming my least favorite.


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## jmsmith (Sep 10, 2011)

nolabama said:


> The first setup the brakes ran off the motor's VFD causing a failure. The current setup the brakes have their own VFD in order to convert the single phase supply to three phase. This bridge is very remote and only has a single phase HV feed. Its all they could justify. All of our motors are standard for supply reasons....so we make the three phase with the VFD. So when the guys said that VFDs kill brakes I had to grab these photos today.


Got ya.... We had three-phase where we were at. Brake coils were fed off 2 of the three phases via contactors. If y'all are feeding your brakes via a vfd, how are you set-up? I guess what I'm asking here is this- is this the only option you have of powering the brakes, can the vfd be programmed to run full-voltage only when activated? Can you go to brake coil with a voltage you have readily available without the need to convert? Just a thot... BTW, am I talkin' sense here???? Have a good day....
-Jim

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## jmsmith (Sep 10, 2011)

Big John said:


> Could you give a bit more detail about each picture? Sounds interesting, but I'm not sure what I'm looking at.
> 
> -John


You're gonna love this, John... I've been on one of these in south Louisiana for BNSF Railroad. These are some real PITAs!
:laughing:

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## nolabama (Oct 3, 2007)

jmsmith - where in mississippi are you


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## nolabama (Oct 3, 2007)

jmsmith said:


> Got ya.... We had three-phase where we were at. Brake coils were fed off 2 of the three phases via contactors. If y'all are feeding your brakes via a vfd, how are you set-up? I guess what I'm asking here is this- is this the only option you have of powering the brakes, can the vfd be programmed to run full-voltage only when activated? Can you go to brake coil with a voltage you have readily available without the need to convert? Just a thot... BTW, am I talkin' sense here???? Have a good day....
> -Jim
> 
> Sent from my iPhone using ET Forum


 It is my understanding the VFD is doing just that - voltage only no curve


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## jmsmith (Sep 10, 2011)

nolabama said:


> jmsmith - where in mississippi are you


Horn Lake, I'm about 5 minutes away from Memphis, TN. Was field engineer and superintendent for a contractor based in AR. Just this past year tested and got my contractors' license here in MS.

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## jmsmith (Sep 10, 2011)

nolabama said:


> It is my understanding the VFD is doing just that - voltage only no curve


Hmmmmm... Would love to see the prints and control scheme on this one... :blink: What I worked was a complete retrofit, including control house with backup genny and submarine cable that was custom- engineered for the job.

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## nolabama (Oct 3, 2007)

jmsmith said:


> Hmmmmm... Would love to see the prints and control scheme on this one... :blink: What I worked was a complete retrofit, including control house with backup genny and submarine cable that was custom- engineered for the job.
> 
> Sent from my iPhone using ET Forum


I just threw a copy away - you would never get a current set - i dont know if i have the one with the brake vfd or not


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## nolabama (Oct 3, 2007)

Photo is of fluid filled brake motor and prox switch that is made (red light is on) mechanic is in white suit behind motor unbolting transmission


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## nolabama (Oct 3, 2007)

this is a photo of the ring gear - concrete is broken up to facilitate the welding repairs to the gear - this is prolly about 30/40 feet in diameter









your only seeing about 3 foot of it - sorry about the thumbnail but its the same as the pic above


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## jmsmith (Sep 10, 2011)

nolabama said:


> I just threw a copy away - you would never get a current set - i dont know if i have the one with the brake vfd or not


NP.... Was just tryin' to wrap my head around this one.... The one I did they were still using the old break house that was out there center-span.... Never seen a bunch of happier Cajuns in all my life as when they saw that old span being barged-off in pieces!
:lol:

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## nolabama (Oct 3, 2007)

The Photo with the drill motor in it is of the output gear that is driven by the transmission that is removed in the photo - its attached to the other motor because the ring gear was not as damaged on the south end

that gear you see is about 5 or 6 foot in diameter - that little box on top of it is a resolver

why we brake the input side of the transmission and not the output side I will never know


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## nolabama (Oct 3, 2007)

jmsmith said:


> NP.... Was just tryin' to wrap my head around this one.... The one I did they were still using the old break house that was out there center-span.... Never seen a bunch of happier Cajuns in all my life as when they saw that old span being barged-off in pieces!
> :lol:
> 
> Sent from my iPhone using ET Forum


last one we barged off was whole


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## jmsmith (Sep 10, 2011)

nolabama said:


> The Photo with the drill motor in it is of the output gear that is driven by the transmission that is removed in the photo - its attached to the other motor because the ring gear was not as damaged on the south end
> 
> that gear you see is about 5 or 6 foot in diameter - that little box on top of it is a resolver
> 
> why we brake the input side of the transmission and not the output side I will never know


Brings back memories.... Not much room to work on things, and at least your span seems to be centers enough you can still use a tug to bring her back!!! When we replaced the motors, we speced them with longer tailshafts and used standard drum-style brakes on the motors... Are the brakes mounted on input to trans, or after gear reduction? Lots of torque difference between the two....

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## nolabama (Oct 3, 2007)

jmsmith said:


> Brings back memories.... Not much room to work on things, and at least your span seems to be centers enough you can still use a tug to bring her back!!! When we replaced the motors, we speced them with longer tailshafts and used standard drum-style brakes on the motors... Are the brakes mounted on input to trans, or after gear reduction? Lots of torque difference between the two....
> 
> Sent from my iPhone using ET Forum


input side - on the rear of the motor

I wish they were on the output side


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## jmsmith (Sep 10, 2011)

nolabama said:


> last one we barged off was whole


The span, brake house, retired ring gear, the top five foot of concrete, old span cabling...... You know, PIECES. :lol:

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## John Valdes (May 17, 2007)

I am not sure I understand this at all. One VFD for two opposing motors? How can that be. Or am I not understanding?
Secondly. A VFD to operate a brake coil? A separate VFD for each brake? What am I missing here?

I would envision each motor having its own VFD and each VFD supplying a signal to turn on and off the brake for each motor. The VFD can turn on an output. The output can energize a contactor or relay to energize the brake.
You cannot use a brake motor on a VFD unless you separate the brake from the VFD motor output.


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## nolabama (Oct 3, 2007)

John Valdes said:


> I am not sure I understand this at all. One VFD for two opposing motors? How can that be. Or am I not understanding?
> Secondly. A VFD to operate a brake coil? A separate VFD for each brake? What am I missing here?
> 
> I would envision each motor having its own VFD and each VFD supplying a signal to turn on and off the brake for each motor. The VFD can turn on an output. The output can energize a contactor or relay to energize the brake.
> You cannot use a brake motor on a VFD unless you separate the brake from the VFD motor output.


One VFD for each motor. At first the brakes ran off of the motors VFD. They now have their own VFD. Just one for both brakes. The idea to use the motors vfd to fire a contactor woulda been smart.


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## Big John (May 23, 2010)

nolabama said:


> this is a photo of the ring gear....


 Looking at the bigger picture, it almost looks like there's a weld broken along the inside circumference of the gear, is that right? 

-John


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## jmsmith (Sep 10, 2011)

Big John said:


> Looking at the bigger picture, it almost looks like there's a weld broken along the inside circumference of the gear, is that right?
> 
> -John


Hey John--
Wasn't tryin' to cut you off yesterday... Hope it wasn't taken that way.... Looks to me like broken weld, also.... VERY bad news on railway swing span!!!

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## nolabama (Oct 3, 2007)

Big John said:


> Looking at the bigger picture, it almost looks like there's a weld broken along the inside circumference of the gear, is that right?
> 
> -John


Beauxcoup brroken welds concrete is busted out even more to facilitate repairs. When it binds up it breaks cogs, concrete, welds, anything it can. If its in full speed motion and the brake slams shut, it breaks whatever it wants.


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