Wiring speed controller - treadmill

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seker
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Wiring speed controller - treadmill

Post by seker » Wed Aug 23, 2006 7:47 pm

Hi - thought should start anew - am struggling to figure out how speed controller off a treadmill (using for other purpose) goes back together (was yr ago and am now lost) got 130 VDC motor (low rpms and torquey) - but can't see if motor works since no longer know how treadmill components were supposed to be connected together
- pics give idea - mainly since there is only 4 blades for controller (AC! [email protected] A+ and A- and plug - transformer - and motor almost has to be some kind of seriesImage
Image

seker
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whoops (no sleep)

Post by seker » Wed Aug 23, 2006 7:51 pm

should be AC1 AC2 and A+ A-

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dacflyer
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Post by dacflyer » Thu Aug 24, 2006 5:34 am

well it would be helpful if you had clearer close up fotos of the board.

but as far as i rember. the choke transformer is in series with the motor,
and it looks like you already have the speed control connected to the board.
so there shouldn;t be much else to connect..usually the motor connections should be marked M1 & M2 or such.. and the power
AC1 & AC2 perhaps..

also look, the tab transistors,,they should goto the motor terminals.. follow it out.

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connections

Post by seker » Thu Aug 24, 2006 6:44 am

there is onlu AC1 AC2 A+ and A- - the speed control is hooked up
(tho A- seems to be less grouped with others as far as board soldering ect)

Since ther are only 2 wires for trans and motor and think motor would need to have both wires + - that would need to splice so that plug into A+ and A- (trans_ then splice go to motor (tho see no evidence that was done this way
- the fact that there is not more connections on board is what is reallly throwing me - know that has to have motor and probably transformer sharing prob A+ A- ? just clueless - had put closeup on already existing thread - will post here when get chance
really stupid that did not label it way back when....

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closeup

Post by seker » Thu Aug 24, 2006 8:49 pm

Image

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philba
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Post by philba » Thu Aug 24, 2006 10:28 pm

This is why I take lots of detailed digital photos of anything I might remotely want to put back together later.

By the way, your cam may have a "macro" or close-up mode. It would be a good idea to use it if you have have it. out of focus or far away pix don't help much.

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jwax
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Post by jwax » Fri Aug 25, 2006 3:27 am

Is it not possible to determine the manufacturer and get wiring info?
Conventionally, AC1 would be hot AC (black), and AC2 is neutral (white).
That would leave A+ and A- for the motor.
Like dacflyer said, the motor will be tied to that bank of 5 MOSFETS.

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dacflyer
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Post by dacflyer » Fri Aug 25, 2006 4:11 am

also i said that that choke/transformer might be in series with the motor.

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jwax
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Post by jwax » Fri Aug 25, 2006 4:44 am

I wonder what is the purpose of the big-ass choke?

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Post by haklesup » Fri Aug 25, 2006 4:34 pm

I'm betting the choke is actually in series with the black wire (AC). Note that there is a fuse holder connected to the plug's black wire, you would need to remove that to plug it onto the PCB, but if you plugged the choke (more like a ballast) there the wires all have a place to go (green just gets bolted to the heatsink). Does the gender of the connectors give any clues, Are all the wires female ends. A series inductor would limit the current without changing the voltage. One would not put this on the neutral return (white).

If AC1 and AC2 have no continuity to the heatsink or any other exposed metal parts, than I would say black and white are reversable but if one is connected to the heatsink, that had better be white. If one goes to a rectifying diode, it would be the black wire but if both go to diodes they are interchangable. (by black I mean after going through the coil it is still the hot AC conductor)

A+ and A- are reversable acroding the direction you want the motor to turn. A properly wired DPDT switch or relay here can make it reversable.

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Edd
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Post by Edd » Sat Aug 26, 2006 2:18 pm

.

OHHHH…BOY…yet another enigma for us to solve…..great shades of Sam Spade.

After looking at all of the composite parts of your “chicken kitâ€

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Re: Wiring speed controller - treadmill

Post by veda » Sun Aug 27, 2006 12:46 am

seker wrote:Hi - thought should start anew - am struggling to figure out how speed controller off a treadmill (using for other purpose) goes back together (was yr ago and am now lost) got 130 VDC motor (low rpms and torquey) - but can't see if motor works since no longer know how treadmill components were supposed to be connected together
- pics give idea - mainly since there is only 4 blades for controller (AC! [email protected] A+ and A- and plug - transformer - and motor almost has to be some kind of seriesImage
Image
Hi,

I think this is a normal thyristor type DC motor controller (no MOSFETS !) but don't see the pulse transformer(s)
Normally a half controlled bridge (2 thyristors + 2 diodes + 1 flyweel diode = antiparallel across the motor)
Mains Input 110VAC on AC1 and AC2 (on the photo you can see the varistor between both phases = overvoltage protection) and Motor Output on A+ and A- (0 to 90 Volt). Put the self (inductor) between the A+ and the motor armature +, thus in series with the motor
The self smooths the motor current (less AC current ripple so less motor heating and also less torque ripple = smoother running)
The big white resistor is the (motor) current sensor (to limit the motor
current). Your 130 VDC motor will not reach the maximum speed but only
70%

Greetings, Dany

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jwax
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Post by jwax » Sun Aug 27, 2006 9:15 am

Thanks Dany, but....
How does a thyristor do any controlling of a DC motor? Are you saying that it chops the incoming AC to provide differing power to the DC motor?
That would require a big-ass inductor to smoothen those power spikes. Guess I don't understand "a normal thyristor type DC motor controller", or how it works.

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Post by veda » Sun Aug 27, 2006 9:44 am

jwax wrote:Thanks Dany, but....
How does a thyristor do any controlling of a DC motor? Are you saying that it chops the incoming AC to provide differing power to the DC motor?
That would require a big-ass inductor to smoothen those power spikes. Guess I don't understand "a normal thyristor type DC motor controller", or how it works.
Hi, a thyristor controller is THE standard for DC motor speed control. Thyristors are use for this purpose since the 60's and are stil used now for this application. The principle = phase control, is just as for a dimmer with a triac (= 2 antiparallel thyristors). They cut a portion out of the mains sinus by delaying the gate puls from 0° (max. Voltage) to 180° (zero). Choppers (PWM) are used when there is no AC supply and only a DC supply is available (e.g. battery)
But as I said I don't see the (gate) pulse tranformer(s), so it could be PWM (Mosfet) chopping the double bridge rectified sinus (120 Hz with zeros in between). This could probably work but this principle is new to me.

Note : the DC inductor is a current smoothing element and is used when the motor armature winding has not enough inductance and need not to be so big.

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Edd
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Post by Edd » Sun Aug 27, 2006 10:50 am

.

After a closer viewing on a monitor with better resolution, compared to the laptop one I initially used, the following becomes more apparent. The small bottom photo shows the inductor having both a male and female insulated terminal outputting. I initially visually perceived dual female connectors.

What seemed like a top view of a grey canned electrolytic, with the now easier visible white top markings, would be more indicative as the knob atop the motor speed potentiometer located below it.

Off center there is a white 6 pin optical isolator/driver ? and at the top left quadrant there are only two pins viewable of probably an 8? pin DIP with the Red leads insulative cover blocking its full viewing. At the top right corner there is SCR symbolization and the ceramic 5-7 watt wire-wound resistor is what one might expect for adjunct SCR snubbing duty unless it is of quite low resistancce value .In that case it just might be a current sensing/limiting resistor as mentioned. Symbolization on a few of the TO-220 cases seem more distinct as power diodes polarizations. Can’t see the bottom to see if only two leads are utilized, though.

(The sole treadmill….. that I once repaired in a relatives home was as simple as checking that the power was present and then checking for DC voltage across IC’s Vcc’s and detecting that there was none present . Seems that raw AC was applied to a dropping resistor and then ½ wave diode rectified and electrolytically filtered and a shunt 1 watt zener then provided regulation. The zener had shorted and was the problem…….easy fix.)
That and an additional of a 130V MOV across the AC line past the fuse was my only final preventative addition.

The integrated circuit at off center board positioning is easily visible as a LM324 quad op amp. Not what one would expect to find, as compared to the utilization of a dedicated all-in-one special/dedicated PWM chip. The four trim pots at the side along with the absence of the electrolytic filter previously mentioned….. all would be indicative of the use of a mere two power steering diodes along with the use of SCR(s) and the LM324 circuitry establishing the variable gate firing level/duration up the slope. The timing being relevant to the different degreee of power output. The smoothing choke would be in series with the motor and the connection to the ‘A’ output terminals, with one being the choke and the other the motor. I would expect the last missing piece of the total apparatus being a missing power switch and its wiring harness for the hot line (Blk) of the AC with its two wires and insulated female push on connectors. One connecting to the open/vacant fuse terminal and the other to one of the ‘AC’ terminals on the PCB with the other ‘AC’ terminal receiving the low (Whi) line cord connector .

Personally, I would probably still use the 100 watt incandescent lamp for initial testing at ‘A’-‘A’ terms. If all is well, the lamp should ramp up and down in brightness in response to the speed adjustment pot. If you will place your ear up close to the lamp you can hear the duty cycle of the motor drive voltage when being changed by the pot. It seems that the coiled filament acts as somewhat of an acoustical transducer…albeit, somewhat weak and inefficient. Should you attempt the same with a PWM controller circuit, it is readily more evident, with them operating on up towards the ~1 KHZ range, where it is even easier hear the changing whine intensity.

Viewing the heat sink of the unit shows two mounting slot holes with the probability of a matching set on the (non viewable) other side. If the controller unit is thermally stressed, the original application may have also had in consideration the additional lateral thermal dispersion to be attained if that alum controller heatsink was mounted onto a large bottom sheet metal panel of the units housing superstructure with those bolts. If it was a plastic/polycarbonate panel…no consideration required.

73's de Edd
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