# Dual Voltage Motor Single Voltage Brake



## Lone Crapshooter (Nov 8, 2008)

I am working on 2 Whiting Corp 35 ton rail car portable jacks. The motors are rated 230/480 wired for 230. The brake is rated for 230. The break is connected across the line and is a 3 phase unit. 
We would like to convert the over to 480 the motor is no problem. 
The control transformer is no problem the phase monitor and line fuse block will have to be replaced .(I am not sure about the fuse block ) The brake is a problem because it is rated for 230 only. 
What I was thinking was thinking was I could reconnect the brake to leads 7-8-9 of the motor but the more and more I am thinking about that is that might damage the motor and might put 277 volts on the brake coil. I have not talked to Whiting Corp about this I just started looking at the jacks yesterday. 

Thanks LC


----------



## Ultrafault (Dec 16, 2012)

What is the current draw of the brakes? You could put in a transformer bank for them.


----------



## Big John (May 23, 2010)

I agree you're gonna be putting 277V across the brakes, so that would seem to nix the idea right out of the box. 

I know that motors can be tapped for small single-phase loads. I don't know at what point that could threaten the operation of the motor, the only piece of info I can contribute is that when we analyze motor windings, we look for anything greater than a 10% imbalance between phases.


----------



## micromind (Aug 11, 2007)

If the motor is WYE wound, you'll have 240 3ø across 4-7, 5-8 and 6-9. 

If it's a 12 lead ∆, it'd be 1-12, 4-7, and 6-9. If it's a 9 lead ∆, it'd be 1, 4-7 and 6-9. 

Just about any size motor can support a brake coil.


----------



## Big John (May 23, 2010)

micromind said:


> If the motor is WYE wound, you'll have 240...


 inch: I guess 480/2 isn't 277.


> ...Just about any size motor can support a brake coil.


 Is there a rule for that, or is that empirical?


----------



## sparkyjim (Feb 25, 2011)

Brakes are mechanically held, electrically released. Most of the brakes I have dealt with are DC. You might want to check the peckerhead to make sure there isn't a rectifier/resistor between motor and brake.


----------



## Lone Crapshooter (Nov 8, 2008)

I have a picture of the the nameplate on the Blackberry and the voltage rating on the motor is 230/460 7.5 HP 20.2/10.1 Amps. 
I really do not how to tell how the motor is wound unless I would take the windings apart and Ohm them out.

LC


----------



## Ultrafault (Dec 16, 2012)

micromind said:


> If the motor is WYE wound, you'll have 240 3ø across 4-7, 5-8 and 6-9.
> 
> If it's a 12 lead ∆, it'd be 1-12, 4-7, and 6-9. If it's a 9 lead ∆, it'd be 1, 4-7 and 6-9.
> 
> Just about any size motor can support a brake coil.


Awesome, I learn so much new stuff here every day. I never considered using the windings on a motor as an autotransformer.


----------



## micromind (Aug 11, 2007)

Lone Crapshooter said:


> I have a picture of the the nameplate on the Blackberry and the voltage rating on the motor is 230/460 7.5 HP 20.2/10.1 Amps.
> I really do not how to tell how the motor is wound unless I would take the windings apart and Ohm them out.
> 
> LC


If it's WYE wound, it'll have 9 leads and the low voltage connection will be L1,T1,T7; L2,T2,T8 and L3,T3,T9.

If it has 12 leads, it's ∆. 

If it has 9 leads and the low voltage connection is L1,T1,T6,T7; L2,T2,T4,T8; L3,T3,T5,T9 then it's ∆. 

The high voltage connection is the same for any 9 lead motor.


----------



## micromind (Aug 11, 2007)

Ultrafault said:


> Awesome, I learn so much new stuff here every day. I never considered using the windings on a motor as an autotransformer.


I've also used the motor windings as a source for pilot lites and solenoid valves. 

If the motor is WYE wound, 120 (or close to it) will appear across T1 & T4 regardless of what voltage it is operating on. Note though, if it's operating on a 480 WYE system, T1 will be 277 to ground and T4 will be 138 to ground. 

If the motor is ∆, T1 & T4 will have 240. There isn't any 120 with this motor. 

The same holds true for T2 & T5 as well as T3 & T6.


----------



## varmit (Apr 19, 2009)

micromind said:


> If the motor is WYE wound, you'll have 240 3ø across 4-7, 5-8 and 6-9.
> 
> If it's a 12 lead ∆, it'd be 1-12, 4-7, and 6-9. If it's a 9 lead ∆, it'd be 1, 4-7 and 6-9.
> 
> Just about any size motor can support a brake coil.


This is the way AC motor brakes have been wired for decades. The brake is single phase 230 volt and is tapped from two of the winding jumper terminations on 460 VAC connected motors- (4-7, 5-8, 6-9). If the motor is connected for 230 VAC, the brake connects with the incoming power to the motor. 

If this happens to be a DC brake, the rectifier supply may have a jumper to convert from 230 to 460.


----------



## micromind (Aug 11, 2007)

Big John said:


> inch: I guess 480/2 isn't 277. Is there a rule for that, or is that empirical?


I would imagine that motor manufacturers have specs, but I've seen 1/2HP motors operating brakes from their windings. 

The smaller the motor, the less current the brake would need. 

So yes, it would be purely empirical.

I love those 50¢ words.......lol.


----------



## Lone Crapshooter (Nov 8, 2008)

These motors have 3 phase brakes . 3 red leads labeled B1-B2-B3 connected to T1-T2-T3 . I always thought electric brakes were single phase even on 3 phase equipment.

LC


----------



## micromind (Aug 11, 2007)

Lone Crapshooter said:


> These motors have 3 phase brakes . 3 red leads labeled B1-B2-B3 connected to T1-T2-T3 . I always thought electric brakes were single phase even on 3 phase equipment.
> 
> LC


The vast majority are single phase. If it has 3 leads, it's most likely a DC coil with 6 diodes in the brake frame.


----------



## JRaef (Mar 23, 2009)

Most of the ones I have seen are DC coils, because the DC coils have less holding power draw, so they don't get as hot and burn themselves out by being energized for the entire time the motor is running. Unless I'm mistaken, I believe that even if they have 3 terminals, it still just feeds a rectifier with a little filter circuit. If your motor comes from one of the larger US based motor mfrs, they tend to use Stearns (brand) brakes, either 57,000 or 87,000 series, both of which come in single voltage and dual voltage versions. You can download the manual for a Stearns brake from Stearns website.

So most likely (one would hope), a dual voltage motor would come with a dual voltage brake, which will have a Low and a High voltage connection, just like the motor will.


----------



## Lone Crapshooter (Nov 8, 2008)

These are on Whiting Corporation Portable Rail Car Jacks . both the motor and the break saw Whiting Corporation They look identical to the ones in the picture. 
http://www.whitingcorp.com/whi_content.cgi?id_num=205


----------

