Help with controlling a treadmill dc motor controller please.

[Ironworker613]

Hi I have a 2.25hp johnson dc motor and a SJED08089IF motor controller board from a horizon cst4.6 treadmill and i am trying to find a way to control it to install it on my milling machine. If someone could help me it would be greatly appreciated! Im going to insert some pictures.

 

[Ironworker613]

Anyone?

 

[IamJatinah]

Hi Ironworker! Well, you picked a hard set to use for your application but there is hope ;o)) The Johnson SJED08089 board and the SJED08092 will not operate without valid feedback from a front roller and the motor encoder wheel, that ugly wheel of death attached to the rear end of the motor shaft, you can see this yes?

Here's what we can do.....if you'd like to exchange that controller for one that will work as you'd like I can do that although I am not sure if this forum allows us to message each other other than on the posts?

I have a rather large assortment of motor controllers that can be cobbled for lathe and milling machines, but this control board would make it a royal pain in the booty, but we can use other styles of controllers and drives.

If you can message me or find me on a google search for jatinah we can maybe fix you up ;o) Basically....you need a pwm control box or board to drive a motor controller, which then drives your motor, I Know, sounds redundant, but it's a safety thing and it's working well in teh industry. Have a great day! ;o)

 

[Minder]

No.1, Johnson are a nice DC motor, in spite of being Chinese.
I think I recognize your post from other forums where it was posted.
If you cannot decifer the connections still, then a KB controller would work, either the cheaper SCR or the better PWM version.
M.

 

[IamJatinah]

Hi All......

I was giving Minder the benefit of the doubt in some past posts, but obviously minder doesn't know I worked for Johnson for many years, know their "2" china factories, JHT1, JHT2 in Shanghai, their facility in Taiwan that makes Matrix equipment, most all the folks at the US facility in Cottage Grove, Wisc, where I was an electronics engineer, and that I know for a fact, the Johnson motor is "not" a good motor.....it will do a job that is true, but as for a good motor I would invite you to a chat about motor design, and if you "think" it's a nice motor please forward your research into it's design, ratios, weights, torques/volt, because I could use some fun reading.

Depending on Johnson Motor and year of manufacture, there can be wide variances. Also, I recall a past post commenting on BEMF that was incorrect as well. Johnson can confirm my identity with a simple call, but that's besides the point.

The motors are "ok".....here are the faults you will find in the Johnson brand of motors aside from the AC motors.....

Magnets have been refined and work well for a DC motor in most all applications thru all ratings, past failures have included burnt windings, disconnected commutator-to-winding connections, shaft softness usually causing a slight bend which then transfers vibrations thru machine, bearing integrity and non-conductive greases(shaft is grounded via it's rear near case) and brush holders.....the motors will do a job, and under most conditions will work fine, but in hot places, heavy loads, and low drive voltages you may see issue's....

This post was about a control board, and not motors....the SJED08089 and SJED08092 control boards cannot be driven without returning feedback from the front roller and "motor shaft encoder"(177 teeth per revolution, count them if you doubt me, I designed controllers for Johnson Health Tech, the parent for Matrix, Vision, Horizon, AFG, Merit, Evolve, Johnson and other brands), the larger Matrix AC motors will use a 12-slotted encoder vs the dc motors which usually have the fine pitch 177-slot/rev encoder.

Decipher connections? Here are your connections....on your 12-pin connector you will have
up
down
motor
pwm
Vcc
Vcc
Speed Sense
Circuit Gnd
Circuit Gnd
Elevation D/A
Elevation Ref Voltage
Not-Used

There they are....no decipher about it ;o) Now, to drive them, ?

Also connected to this control board....

3-PIN Elevation Drive connection to front of board near relay sets(red, black, white)
2-PIN Speed Sensor connection from reed switch at front roller
5-PIN Encoder connection coming from the rear of this particular DC motor
12-PIN console cable as described above in precise detail
3-PIN Elevation feedback pot connection to control board
2 MOTOR WIRES
2AC Line wires


remove the 2-pin connection, controller will not run
remove the 5-pin connector, controller will not run
remove the 12-pin connector, controller will not run

And....finally....when any dc motor comes to a stop or is "relaxed" it will generate back electro-motive-force or BEMF. This must always be taken into account during design or you will absolutely rip switches and control logic.
;o)

 

[Minder]

I only go by my personal experience and so far have not had a real problem with the Johnson T.M motor in a CNC spindle applications, using pic based PWM controller and rpm feedback.
https://www.johnsonfit.com/blog/treadmill_drive_motors_and_the_question_of_horsepower
M.