Bypass motor on motor help

[bline22]

Hello,

I am green when it comes to this and I hope this is the right place to ask this question.

I have an elliptical machine that the motor is shot. This motor provides a stride functionality that we don't even use.

I talked with the Vendor and they said that even if you don't use it you have to replace the motor for a crazy dollar amount to get the machine to function.

There look to be 4 wires going from the motor to a circuit board. Is there a way to simply trick the system in to thinking that motor is just fine.

Here is really where the green in me is going to show. Could i determine which of the wires i need to cut lets say and perhaps join together to make it work? This would be assuming there is no board or anything internal that is sending codes back to verify functionality lets say I guess. I don't want to do this to then fry the board to have even more that I would need to invest here but if this might be possible maybe we can figure out how to do it safely.

Anyone ever done anything like this or am i up a creek spending the money to make this thing work?

Thanks for the help.

 

[Minder]

How did you determine the motor is shot?
Does the motor normally run even when the function is not engaged?
How many wires to the motor?
Does the motor have any electronics attached to it or a slotted wheel pulse counter wheel or?
M.

 

[bline22]

wow thanks for the reply and so quick.

I determined the motor was shot via the manufacturer and i had the machine run through some diagnostics. the only thing you get with the diagnostics however is a pass fail. When it ran on the side that does work it would move the motor a bit, then stop, move it, then stop. The intent of the motor is to shorten and lengthen the stride. knowing the other side works i did do a swap of the cables and then i received the error on the inverse side so the manufacturer said it is not the board and is the motor.

#2 when you turn the machine on the motor runs through a very brief turn on turn off. 3 seconds maybe. Guessing it is a short diagnostics or re-calibration perhaps. After that it turns off and we jump on it doing nothing with it. (we leave the stride at the default)

#3 there are 4 wires you can maybe see the one square showing the wires. that is the motor wire.

#4 i can't tell that there are any electronics. I would guess there are not but not sure what is inside the housing of the unit. As far as the wheel questions I am not sure what you mean there. Does the picture help?

 

[Minder]

That appears to be a linear actuator, normally they are DC motors, I am guessing the red and blk are motor, the other pair could be a limit sw, or?
.Can you measure the resistance of the BLK/RED pair.
If it can be determined which is the motor pair, you could apply an external DC voltage to it, an automotive battery is a good source.
M.

 

[bline22]

Unfortunately I can't answer your question there. I am not sure if it is a limit sw.

I can perhaps measure the resistance. Can you give me some brief steps. I have a resitance meter but not sure how to use it to get you the info you need?

When you are mentioning using a automotive battery to it are you thinking to see if we can get he motor to move? Or, to perhaps validate that the red and black are what are providing power to the motor?

 

[Minder]

Usually with this kind of problem and very little to no manuf. data, you have to do a little reverse engineering and find out specifically what you have in order to pin the cause down.
If you have not used this function, or very little, it is hard to believe the motor is shot.
Linear actuators are a little harder to diagnose as it is not possible, or very hard to back feed the motor and turn it into a generator to see if there is anything on the leads in order to identify the right connections for the motor, it may come down to doing a little dismantling, you have very little to lose anyway.
You really need to be a little experienced on using a meter and interpreting the results.
Again, I find it hard to believe that a seldom used motor assembly requires replacing when almost never used.
To use a timely example. my 35yr old central vac went belly up yesterday, on dismantling it, it was found to be 2 $2.00 bearings, the manuf wanted $200.00 for a motor!
M..

 

[bline22]

I understand and is exactly how i feel. This thing should not be broken.

It is OK to be frank with me here but i think you are telling me too that perhaps this is outside of my knowledge in attempting to either bypass whatever check is occurring?

If not, is there a youtube video i could pick up that might be close what you are asking me to check that i could watch and get an idea on the basics to get the job done?

I will have to take this apart like you said anyway so I might as well get on that today and at least see if there is a board in there perhaps and see if i can better notice any visible signs of damage.

I attached a picture of some further details of the motor as well if that helps.

Appreciate the information and help

 

[Minder]

I would check to see if you can remove the linear actuator for further testing, I am guessing that the cost is for replacing the unit as a whole instead of just the motor.
See if you can identify any wires going into the motor directly, I see the motor is a 24vdc version so a large battery such as automotive could be used to test it, you would need to energise it momentarily to see if it was already at one end of the stroke. If the unit appears to work, then it could be the board that is feeding the unit.
Being a little mechanically inclined also helps.
M.

 

[bline22]

Thanks again for the help. I am a little mechanically inclined and handy but just don't know a heck of a lot about electronic repair.

I have the motor off finally. i had to go and get some c clamp pliers but got it off today. There is a small board in there but seems clear which wires go to the motor but thought I would run it by you to be sure.

Is there anything I would need to check here?

I would guess the red is the positive and the brownish one is negative?

Anything obvious to you here too to try and bypass it if the motor is truly shot?

Thoughts on next steps?

Thanks.

 

[Minder]

A little late getting back but the red/blk (Brn/Red) appear to be the motor wires and the yellow/white are the reed switch inside for stop position.
The motor wires will alternate polarity dependant on direction.
See if you have continuity across the motor connections, I imagine the reed sw will show open if it is activated at an extreme position.
M.

 

[bline22]

Thanks for the reply.

The only places I am seeing there is continuity is between the following
red to red
brn to blk

 

[Minder]

If the red to blk shows open, then it does appear to be something in the motor, I would tackle taking the motor itself off if possible, and see if anything obvious, which sounds like a brush open circuit?
M.

 

[bline22]

So i can get the top cap off but I don't know much about this either i admit.

Here is a picture. Best I can tell there doesn't seem to be anything out of sorts here. the portion that should spin seems to.

What in these motors can go wrong?

If the motor is shot, is bypassing the check an option to trick the system in to thinking the motor is fine?

 

[Minder]

OK check the continuity across the two connections to the brushes, also check the leads from brushes to the circuit board.
There is very little to go wrong, the motor itself looks in good condition.
Barring a flaw in manuf. I suspect the fault is minor in nature.
Bypassing depends on what the controller expects to see in the way of limit switch status.
M.

 

[bline22]

So here is what I checked so far. You might notice if the image comes through that there are 3 boxes i highlighted on the image. The very top 3 is a switch i think that gets tripped when the mechanism extends to a limit. there are 2 of these. both of switches i made closed so it would allow the continuity check to pass. I checked it and it has continuity.

I then plugged everything in and I have continuity from the motor red wire to the red wire on the reed(?) switch is that right. Also, i have continuity from the black wire (red box) on the motor to the brown wire on the reed sw(red box).

When i would check the black wire to the brown wire on the reed sw i would have my son trip the 2 switches to make sure they worked and I all looked good.

What else can we check here do you think or what is your gut telling you?

 

[Minder]

I would have expected the motor and the reed switches to go back to the controller separately, as they appear to.
The controller would need to be connected directly to the motor, or at least short the SW's out in order to run.
What would be a good idea would be to draw it out diagrammatically from where the 4 wires enter the unit.
M.

 

[bline22]

I am not sure what you mean on diagramming it out? Can you give me some pointers on that?

 

[Minder]

It doesn't have to be done with a fancy drawing package, just a hand drawn sketch of the wires and where/what/how they are connected .
With wire colours.
If you are not sure how to draw a certain component, you can google Electrical symbols etc.
Telemecanique wiring diagrams

M.

 

[bline22]

How does this look? This is my first time attempting this at the lower end of this you will see the 4 wires. those are from the main board. that thing I would have to see if the manufacturer might have a schematic as that is beyond my abilities with all the resisters, capacitors and not know how stuff is connected on there.

I simply did the below in visio. Is there stuff you would expect that I am missing on this ruff drawing?

 

[73's de Edd]

.

Sir bline22 . . . .

I think that you are doing G.R.E.A.A.A.T .
Considering initially putting the case back on the motor.
If you can get twelve volts from a car battery over to the motor RED terminal of the motor with the positive + terminal of the car battery. And then use the negative terminal of the battery to make a very fast temporary touch connection to the black connection of the motor to see if the motor spins a bit.
That's loooooooooking gooooooood for the motor .
Then if you can clip connections between your motors far left Red connection and the battery positive+ connection and then the batteries negative to your drawn in Brown wire.
That will let you then try out the possible 4 switch combinations that you can switch between with those roller / leveraged microswitches . At one of those combinations, both switches will be closed and your motor could run again.
That motor power aspect of the assembly might then be considered minimally OK, with next attention being directed to the magnetic reed switch .
It has a ceramic magnet that is driven by the motors armature. The magnets two poles rotating in the close proximity of the reed switch causes its contacts to open and close . That is providing your speed / activity pulsed information that is being needed by your control electronics .
If you find the motor running, which I think that you will, you can then check out that reed switch activity's information either by the use of a voltmeter or an ohmmeter.
Either Sir Minder or I . . .et al. . . . can prompt you procedurals, on that further testing.

73's de Edd