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Brent Cxc Wheel Problem: Full Speed At Power On And Trips Circuit Breaker


solarvalue
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Dear forum members,

 

I am a potter from Australia and have stumbled upon your forum searching for some help with my Brent CXCK pottery wheel. The problem is that, upon powering on the wheel, the motor runs at full speed until, a few seconds later, it trips my house's circuit breaker. The position of the foot pedal does not seem to have any bearing on this behaviour.

 

So far I have:

1. Replaced the foot pedal speed control assembly with no change.

2. Tested the new speed control assembly with my multimeter. There is a resistance of 0.661MΩ when fully off and a resistance of 0.245MΩ when fully on.

2. Replaced the power cord with no change (it was worn and needed replacement anyway).

3. Tested the power switch (it is good).

4. Checked all connections and wires which look good.

 

After replacing the speed control assembly, I thought it might be an issue with the motor but, seeing as the position of the speed control does not change the speed of the motor and the speed control assembly is new, I think it must be a problem with the controller board. That is unless Brent sent me a bad speed control assembly.

 

Any ideas which components on the controller board might be bad?

 

Thanks in advance.

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After trying a different as Ron suggested, try disconnecting the foot pedal and turning it on. If the problem persists, then there is probably a short in the control board. If disconnecting the foot pedal takes care of the problem, then the problem is probably in the foot pedal. Many foot pedals use a simple potentiometer to control speed. You might try to wire in a pot by itself and if that works, then the problem is in the foot pedal. Change the pot in the foot pedal or replace the entire foot pedal.

JohnnyK

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Guest JBaymore

What ELSE is plugged into that breaker that controls that outlet?

 

My CXC is plugged into a dedicated 20A 110VAC outlet.  They draw some amps. 

 

You might just be exceeding your breaker's amperage.

 

best,

 

...................john

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Thanks for the replies everyone. Great community here!

 

It a international call but how about calling Amaco /Brent and talking to them?

 

I'll shoot them an email and see if I can get a response.

 

In the meantime:

 

Did you try plugging it in a different outlet?

 

I tried another outlet on a different circuit, it still tripped the breaker.

 

After trying a different as Ron suggested, try disconnecting the foot pedal and turning it on. If the problem persists, then there is probably a short in the control board.

 

OK, I tried this and with the foot pedal assembly disconnected, the motor is still running at full speed on power up. So it's not the pedal and likely a problem with the control board. Does this mean that the transistor on the control board is bad? Or could it be some other component?

 

 

 

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Brent is not great about respond to e-mails-I still would venture a call even with the time zone differences . They sell a new control board-If I recall its about $100.

 

OK, thanks, if I don't get a response I'll call. The control board is otherwise in good shape, I would rather just replace the faulty component if possible, I have soldering skills so it won't be a problem if I can figure out what the issue is.

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There was a thread on if I recall right the power part of that board. It may have been a few years ago. It may take some digging but that may help you if you can find it. It was specifically about the Brent control board.

I may have printed it and put it out in Studio with my Brent spare parts. I will take a look in next days.I'm on a studio free time off for yearly tax work.

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Australia has a different voltage (and frequency but that shouldn't matter for a motor). I never saw Brent wheels in New Zealand and would not be surprised if they only make a 110-120V model. There should be a plate somewhere on the motor that lists the required inputs and maximum amps and such.

 

I have an Australian (Venco) pugmill. To make it work I needed a voltage converter. I predict you will need one too.

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Australia has a different voltage (and frequency but that shouldn't matter for a motor). I never saw Brent wheels in New Zealand and would not be surprised if they only make a 110-120V model. There should be a plate somewhere on the motor that lists the required inputs and maximum amps and such.

 

This is a 220V model which is the correct voltage for our supply. The wheel was working fine before this problem occurred.

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Guest JBaymore

Posted Today, 01:54 PM

solarvalue, on 10 Jan 2017 - 11:15 PM, said:snapback.png

  Does this mean that the transistor on the control board is bad? Or could it be some other component?

 

Or could it be some other component?

 

Here's my take on this issue.......  some could be wrong.

 

There are no transistors on that board.  You have a bunch of diodes, some capacitors, a rectifier diode, a triacs, a silicone rectifier, and resistors. You are maybe mistaking the rectifiers for transistors.  They come in a somewhat large "packages" .... single component...internally multiple components.

 

The whole foot pedal unit is just a variable resistor in that circuit.  It is made up of three separate variable resistors (potentiometers). As the resistance threshold and total resistance is varied... the speed of the wheel motor is varied.

 

When the foot pedal is not there...... the R (resistance) value of that part of the circuit is then infinite.  So that effectively removes the connection between D6 (diode) and the point between R1 and R3 (resistors).  Those two circuit traces connect to the wire that goes to the main rectifier and then the foot pedal. 

 

This is a total GUESS... but look for a break or bad solder joint on the pcb (printed circuit board) trace (little metal "wires") that runs between the wiper on the hi-potentiometer (on the line that connects to the footpedal connector)  and the trace that connects to d6 (a diode) ...which will connect to the other wire on the foot pedal.  Apparently from your description it is seeing infinite resistance whether the pedal is connected or not.  It is not "reading" the pedal.

 

Also look for a bad solder joint in the foot pedal connectors themselves, or a broken wire in the lead. (Use a multimeter on the pedal leads.)  Same look-see in the foot pedal itself. 

 

Hope that might be of help.

 

best,

 

......................john

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Don't overlook the mechanical 'thing-ah-majig' that translates the foot pedal up/down motion to a rotational position of the potentiometer.  The 'thing-ah-majig' can be addjusted to limit the speed range of the wheel.  The discussion so far indicates to me that the 'thing-ah-majig' needs to be adjusted so that the beginning position is at zero rpms.  At least check it.
 
LT

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Let us know how this turns out please??

 

Don't worry, I'll be sure to update the thread with any new developments.

 

I've been at the beach, just getting back into this now.

 

This is a total GUESS... but look for a break or bad solder joint on the pcb (printed circuit board) trace (little metal "wires") that runs between the wiper on the hi-potentiometer (on the line that connects to the footpedal connector)  and the trace that connects to d6 (a diode) ...which will connect to the other wire on the foot pedal.  Apparently from your description it is seeing infinite resistance whether the pedal is connected or not.  It is not "reading" the pedal.

 

Also look for a bad solder joint in the foot pedal connectors themselves, or a broken wire in the lead. (Use a multimeter on the pedal leads.)  Same look-see in the foot pedal itself. 

 

Thanks for the suggestions, John. Looking into this now.

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Here's the back:

 

post-81397-0-14803700-1484539592_thumb.jpg

 

I can't find any broken traces or bad solder joints.

I got an email back from Brent, they wan't me to buy a new board. I'm a little hesitant to do this seeing as I just bought a new pedal speed assembly and it didn't fix the problem. I'm worried that I may get a new board and it won't fix the problem. The other thing I could try is replacing some/all of the components on the board, that would likely be a lot cheaper. Any ideas?

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I'm not an resister guy-I have a soldering iron and use it but the board is not my deal.I leaned all that in the 60's and forgot it from lack of use. I will say Brent these days seems to be with the younger techs heading into just replace this or that until its fixed.I miss the old days with folks who actually knew all the parts and what the real fixes are.Now its the board or the foot pedal or the motor-not what is it with the board or the foot pedal or the motor.

 

I consider this like many of the things we have settled for this days 

crappy phone connections vs land lines

poor sound in MP3s vs quality stereo sound from old school amps and speakers

 

You can start by testing all the board components separately but I think they need to be disconnected 

One last note they had controller issues with one model for a spell-check out the archives to see if this is your model?

what year and controller is this-brants site shows all the controllers in a photo.

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