MotorGuide Mosfet repair question.

chan93lx50

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Apr 28, 2005
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Okay picked up a 104lbs thrust motorguide for cheap knowing that it has a bad mosfet. I know one option is to convert it to digital for $350 to $450 bucks. I am looking at the other option by changing to to a 5 speed dial instead of a variable speed which in turns gets rid of all the computer crap in the motor.

I am looking for someone whom has done this and find out exactly what parts are needed to accomplish this task.

I know some places sell a kit that includes new brushes and rear caps, but I am willing to use the old ones as I know they still are functional since the motor does work on High speed.

I just would like to find out what exactly is needed to make the conversion so any input would be great.

Thanks
 

asm_

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Apr 11, 2010
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Re: MotorGuide Mosfet repair question.

I am looking at the other option by changing to to a 5 speed dial instead of a variable speed which in turns gets rid of all the computer crap in the motor.

Based on that statement, I'm guessing you are not going to repair MOSFET? How do you intend to control the speed of the motor?? Or are you just going to run all either on or off?

B
 

Silvertip

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Sep 22, 2003
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28,771
Re: MotorGuide Mosfet repair question.

There is one way to do this but finding the wire wound resistors that fit into the motor housing may be an issue. You would need to find the five speed switch or rig a Radio Shack switch (six positions since you need off). Each switch position selects one or more wire wound resistors to provide the desired speeds. All you need to do is determine which resistance provides the desired five speeds. Getting the idea this is not a simple job?
 

asm_

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Re: MotorGuide Mosfet repair question.

Without using MOSFET as switching gate to control the flow of electron, you are left with either full power on or off. Using resistor to control motor speed is essentially burning off energy not used by the motor as heat using resistors. Since you will buring off a lot of energy using resistors, I wouldn't be surprise you end up needing a pound or two of expensive ceramics resistor arrays.
 

chan93lx50

Cadet
Joined
Apr 28, 2005
Messages
21
Re: MotorGuide Mosfet repair question.

Ahh yes but take note of the following diagrams of MotorGuide trolling motors this is from a 24volt 67lb thrust trolling motor

http://www.boats.net/parts/search/M...olling Motor(Model EF67) (24 Volt)/parts.html

http://www.boats.net/parts/search/M...Wire Diagram(Model EF67) (24 Volt)/parts.html

http://www.boats.net/parts/search/M...ssembly(67# - 5 Speed) (MVF397012)/parts.html

There is no Mosfet used, only a Rotory switch in the pedal, this is what I would like to try to convert too..............
 

asm_

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Apr 11, 2010
Messages
245
Re: MotorGuide Mosfet repair question.

Unless I am missing something. The rotary switch only control which wire used to send power down to the motor. I can only guess perhaps the motor has few different set of winding that can be used individually or in any combination to achieves the goal of varying its speed.

You can certain do something similar, but you'll either need to rewind the motor or purchase a different motor with such capability already builtin.

B
 

Silvertip

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Sep 22, 2003
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28,771
Re: MotorGuide Mosfet repair question.

These are two entirely different motors. That five position switch was explained very nicely and at $12.00 you know it contains no electronics. The variable speed motor is electronically controlled. The motors themselves do not interchange.
 
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