Think I have the Wing reverse wiring figured out for the trike.

[John Schmidt]

Recall I picked up a Wing motor with reverse which I plan to install in my trike. Mechanically it's ready to go in, having done some major changes and upgrades while in the process. The only issue was wiring it in such a way as to have a more moderate reverse speed, keeping in mind SteveK's comments regarding his reverse installation. It was quite fast and he had to moderate it by just tapping the start button for intermittent use.

With the help of my friend Stu Saunders, known here as Pluggy, and a few hours on the Wing schematic, we came to understand how the lower speed was attained. The OEM setup in the Wing uses a sort of shunt with 3 resistors to ground, all in parallel with each other and the motor. Today, after picking up a Wing resistor pack off Ebay, and using the battery cable to starter motor set up, I wired it in to test the rotational speed of the starter which is already installed in the engine. The first test was directly from battery to the starter & it spun up quite fast. Next, I wired in the resistor pack in using only one resistor, then hit it with the battery again. Bingo...it runs noticeably slower.

The 3 resistors are in parallel in the sealed pack, each one appeared to test out at around 1.7 ohms so in the single resistor application above a single resistor would give the most resistance and slower speed. Tyng 2 together would halve the resistance to ~.85 ohms which should have increased the rotaional speed of the starter but instead seemed to slow it down even more. Back to the drawing board for answers. I'm tossing around the idea of using a separate push button to activate the reverse, the start button isn't that robust so why test it further, plus I might install a three-way switch, thereby allowing me to go from one to two resistors if/when needed. I'm trying to get it all planned out prior to making the engine swap so I don't have do all the testing & head scratching after it's installed.

[WintrSol]

Very curious that decreasing resistance also decreased the speed. Got a link to that schematic? I may spot something you have missed that explains this. At any rate, I'm just curious.

[Timbo1]

Very curious that decreasing resistance also decreased the speed. Got a link to that schematic? I may spot something you have missed that explains this. At any rate, I'm just curious.

Resistors in parallel reduce the resistance. Resistors in series add to resistance so he actually increased resistance in line by removing 1 resistor.

For example:
3 - 20 Ohm resistors in parallel equals 6.7 Ohm
2 - 20 Ohm resistors in parallel equals 10 Ohm


3 - 20 Ohm resistors in series equals 60 Ohm
2 - 20 Ohm resistors in series equals 40 Ohm

[The emperor has no clothes]

Very curious that decreasing resistance also decreased the speed. Got a link to that schematic? I may spot something you have missed that explains this. At any rate, I'm just curious.

Resistors in parallel reduce the resistance. Resistors in series add to resistance so he actually increased resistance in line by removing 1 resistor.

For example:
3 - 20 Ohm resistors in parallel equals 6.7 Ohm
2 - 20 Ohm resistors in parallel equals 10 Ohm


3 - 20 Ohm resistors in series equals 60 Ohm
2 - 20 Ohm resistors in series equals 40 Ohm

Good catch ! It’s been a long time since I had Basic Electronics class in the Navy. I’d forgotten all about that. 

[John Schmidt]

Yup, figured it out late last night, Stu texted me early today and his analysis was the same. Two resistors in parallel halved the resistance, thereby increasing the current flow through that part and less current through the motor. That explained why the starter turned even slower with 2 rather than 1 resistor. I'm like Rob, been a looong time since I've done any kind of work like this so you tend to forget. I knew about resistors in parallet as compared to series, just the effect it had on current flow to either branch of the circuit had escaped me. I'm not a Rembrandt but will try to draw the basic circuit for the starter in association with the 3 resistor shunt.

This is the basic schematic drawn by Pluggy, I added the extra resistor to the left. If I connect it at the base of the of the first one it slows the starter even more, based on the statement above.

[WintrSol]

That implies that the cable providing the power is current limited, and that its resistance become significant enough to reduce the Voltage when the resistors increase the total current. It also means that the source cable it heating up, limiting the time you can use reverse. Do NOT change that cable for a heavier one, as it will not drop the Voltage enough to reduce the speed as much.

[John Schmidt]

That implies that the cable providing the power is current limited, and that its resistance become significant enough to reduce the Voltage when the resistors increase the total current. It also means that the source cable it heating up, limiting the time you can use reverse. Do NOT change that cable for a heavier one, as it will not drop the Voltage enough to reduce the speed as much.

I have the factory starter cable which comes with three connections. One for 12vdc, one to the resistor pack, one to the starter. A relay will determine whether the power goes direct for starting or puts the resistors into the circuit. The resistor circuit has a 65 amp fuse in it so you know there's some current flowing there. It's been an interesting project thus far...both converting the Wing motor to use in the Valk and coming up with a method/circuit to control the reverse speed. I'm debating installing a 3-way switch for the resistor pack to allow me to choose whether I want one or two resistors controlling the speed. I won't really know until I see how it works with the heavier trike.

[Timbo1]

For future reference if you keep in mind Watt's law and Ohm's law you can pretty much figure out any basic circuit with a little algebra.

Watt's Law:
Power (P) = Amps (I) x Volts (V)
So P/I=V & P/V=I

&

Ohm's Law:
Volts (V) = Amps (I) x Ohms (R)
So V/I = R & V/R=I

In your case Volts are static at roughly 12V.  So using my example of 20 Ohm resistors in parallel from earlier post.

12V / 6.7 Ohm = 1.79A  and  Power = 12V x 1.79A = 21.48W (Watts)

12V / 10.0 Ohm = 1.20A  and   Power = 12V x 1.20A = 14.4W (Watts)

So by increasing resistance it will reduce Amps and also reduces Power.

Basic electronics from the late 80's so that's about all I can remember.  Hope it helps.

[WintrSol]

So, does something switch the resistors on when reverse is selected, or is there a separate cable for starting normally?

[John Schmidt]

So, does something switch the resistors on when reverse is selected, or is there a separate cable for starting normally?

Yes, there's an internal switch that's activated when you engage reverse mechanically. The electrical aspect is then controlled via relays and a "reverse control unit" which I don't plan on using. Here's a pic of the starter cable. The left end is 12v source connection, the far right is attached to the resistor pack which is connected to ground, and the short piece is attached to the motor. Tomorrow I'll take a picture of the resistor pack and show how it's all connected. Keep in mind, 12v is applied to both the motor connection and the resistor connection, which in turn is grounded causing the reduction of current flow to the motor and reduced motor rpm. Those Japanese engineers were pretty smart, if you simply tried to reduce voltage to the motor you'd need a resistor the size of a can of Pepsi...and a rather large set of cooling fins. 

[WintrSol]

Those Japanese engineers were pretty smart, if you simply tried to reduce voltage to the motor you'd need a resistor the size of a can of Pepsi...and a rather large set of cooling fins.  

But that is what must be happening; there must be some resistance upstream for the resistor pack to function, by dropping the Voltage enough to reduce the current into the motor. Or, the combined load is actually too much for the battery to supply, which isn't doing much for its life span.

Now, I'm really curious to see a wiring diagram.

[John Schmidt]

The resistors are in parallel with the motor, thereby reducing the magnetic field. The result is like making the motor smaller. The reverse schematic takes up 3 pages in the Wing shop manual so I'm not taking pics of it. The link shows what the resistor pack looks like, the starter cable attaches to the bolt adjacent to the three resistor wires. Those 3 wires are grounded but not all at the same time.


https://www.ebay.com/itm/164192434487?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D5c0683a3c456437eb3e5b25d0b0eee7f%26pid%3D100675%26rk%3D9%26rkt%3D15%26sd%3D263744369408%26itm%3D164192434487%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A31be69b9-3e0e-11ed-9896-066959785ef3%7Cparentrq%3A7cd420791830a60c137b85cbfffee9c8%7Ciid%3A1

[WintrSol]

The resistors are in parallel with the motor, thereby reducing the magnetic field. The result is like making the motor smaller.

I'm sorry, but motors don't work like that. The only thing that can reduce the magnetic field is less current, and, for the resistors to do that, they have to work against another resistance to reduce the overall Voltage at the motor.
Maybe I can find a copy of the manual on line by searching for that model year.

OK, I found this: https://www.goldwingfacts.com/threads/gl1500-color-wiring-diagram.636674/
Two resistors are in series with the motor when the motor is activated, and the third bleeds some of the current into the ground through that fuse; how many are active determined by the power required of motor, and are selected by the speed limiter and power control 1 & 2 relays, when only starter relay switch A is on. Clever design, but you need all those relays working to control the motor when in reverse.

[John Schmidt]

FWIW...I have a Wing shop manual and the reverse drawing shows the three resistors in the pack are in parallel with the starter. They attach at the same point as the battery cable on one end and grounded at the other. I have hooked it up in that fashion this past week, first w/o the resistor pack, then one resistor, then two. All resistors were attached at the 12vdc point on the starter and grounded at the other end, just like in the schematic. The first run w/o resistors spun the motor over with gusto. The second run with one resistor the motor spun at a noticeable slower rate. The third run with two resistors spun the motor even slower. The starter is installed in the engine and you can watch the clutch(cover still off) as it spins. Very easy to see the difference with each application.

The following is an excerpt from my friend Stu(aka Pluggy), who has a greater understanding from an engineering standpoint than I.
"Starters are series wound motors which makes the motor work like a resistor in a current divider. A resistor in parallel with the motor will simply rob it of some of its energy."

In my case and as shown in the schematic, by adding two resistors in parallel to the motor will halve the resistance, creating a path of less resistance for current than the path through the motor. Greater current through the resistors, less through the motor...thereby slowing it down. It worked in that fashion on my former '92 Aspencade, and it worked in the same way in my Wing motor sitting on the hydraulic work table. I plan to start pulling the current engine out of the trike in the near future in hopes of having it all up and running for the next riding season. Here in Wisconsin, that might not be until next May...considering they had a snow storm on Mother's Day 2-3 yrs. ago.  

Re. the comment "motors don't work that way"...keep in mind that less current means a less powerful magnetic field. Less current through the motor is accomplished via the resistors in parallel.

[WintrSol]

But the resistors in parallel can only take some of the current from the motor if the source is limited. For that to be true, either the battery is limiting the total current, or something between it and the motor is. Without this limit, the resistor only increases the total current, which is why the drawing I found shows two in switched in series.
Think of it this way: plug a light into an outlet, and a toaster in next to it, note that both are resistive; does operating the toaster dim the light more than just a little? Same principle - the only thing limiting the current is the wire between the outlet and the breaker panel.
I found a copy of the full service manual online, and on page 18-3 is a drawing of the starter/reverse wiring, which is the same as the one I linked above, but without color.

[Timbo1]

Voltage in a parallel circuit is the same at each leg.  Total current is the the sum of each drop across each component.

Current is the same in a series circuit.

It makes more sense to me the resistor pack to be in series to the motor due to the current limiting that occurred when 1 of the resistors in the parallel resistor pack was removed from circuit thereby increasing resistance to the load.  With increased resistance in a series circuit current would be reduced.

[John Schmidt]

Here's a block diagram taken from the 1992 Electrical Troubleshooting Manual and covers all three models of the Wing. It's easier to follow than the expanded link you gave us even with color, which in itself makes it much easier and worthy of bookmarking.  

[WintrSol]

That makes sense, if you realize power comes from Starter Relay A to both inputs BB and EE. Power from BB goes directly to the rightmost resistor to the motor. Depending on how much power the motor needs, Power Relay Control #1 and #2 may also send the power from BB through the other two resistors. If the motor is getting too much power Control #2 would be turned off and Speed Limiter Relay would turn on, bleeding some of the power from the motor end of the two right resistors to ground, or at least the right most resistor, if Control #1 was turned off to reduce power. So, you have at least one resistor in series with the motor, and possibly all three in parallel and fed to the motor for maximum speed. Or, you can have one resistor in parallel to the motor to siphon off some of the power provided through one or two resistors. I suspect, from the labels, which relays are closed or open depends on the Voltage monitor, and that monitor controls the reverse control unit outputs.

[John Schmidt]

"one resistor in series..."
No...in parallel.

If any or all of the resistors were in series with the motor, there would only one lead at the B+ attachment point. However there are two leads attached there, both from the same source...the battery, but by different routes. The resistor(s) are in parallel with the motor as shown in my much simplified drawing earlier in the posts. I'm done here!

[RP#62]

That makes sense, if you realize power comes from Starter Relay A to both inputs BB and EE. Power from BB goes directly to the rightmost resistor to the motor. Depending on how much power the motor needs, Power Relay Control #1 and #2 may also send the power from BB through the other two resistors. If the motor is getting too much power Control #2 would be turned off and Speed Limiter Relay would turn on, bleeding some of the power from the motor end of the two right resistors to ground, or at least the right most resistor, if Control #1 was turned off to reduce power. So, you have at least one resistor in series with the motor, and possibly all three in parallel and fed to the motor for maximum speed. Or, you can have one resistor in parallel to the motor to siphon off some of the power provided through one or two resistors. I suspect, from the labels, which relays are closed or open depends on the Voltage monitor, and that monitor controls the reverse control unit outputs.

Maybe I'm reading it wrong, but it looks like BB is a ground.  When Power Control Relay #2 and the Speed Limiter Relay are energized, it connects the negative side of the battery to BB and on to two of the resistors.  When Power Control Relay #1 is energized, all three resistors are given a ground.  When any of the resistors gets a ground, it puts a load in parallel with the motor.  The number of resistors getting a ground, varies the load being put in parallel with the motor.  That's what it looks like to me anyway.

-RP

[WintrSol]

Well, the top of his diagram is cut off so the label is gone, but if you examine the full schematic, Starter Relay A switches battery (+) to Starter relay B, and also to Power Control relays 1 and 2 and also to one of the resistors (rightmost on the diagram), the other side of which goes to the motor (+). Power control relay 1 can apply this power to the leftmost resistor, so it is parallel to the first powered resistor, and doubles the current to the motor. Power control relay 2 can apply power to the center resistor, so triples the current to the motor, because all three resistors are now in parallel, and between the relay A output and the motor (+); relay 2 must be switched off before the Speed Control relay is turned on, or you get a direct short of the power from Starter Relay A to ground, and blow that fuse. With relay 2 off and the Speed Control relay on, the center resistor is connected to ground and siphons off some of the current coming through the rightmost resistor, and maybe also the leftmost resistor, thus reducing the speed some.

Maybe I'm reading it wrong, but it looks like BB is a ground.  When Power Control Relay #2 and the Speed Limiter Relay are energized, it connects the negative side of the battery to BB and on to two of the resistors.  When Power Control Relay #1 is energized, all three resistors are given a ground.  When any of the resistors gets a ground, it puts a load in parallel with the motor.  The number of resistors getting a ground, varies the load being put in parallel with the motor.  That's what it looks like to me anyway.

-RP

For those who need pictures, look at this closeup of the diagram:

The BLK wire from relay A changes to red at the splice above the speed limiter relay, and goes to the control relays AND a resistor, while the blue wire goes to relay B. The other side of that resistor connects to another BLK wire that goes to the motor. The output of control relay 1 is also BLK, while that of relay 2 and the speed control relay are gray (labeled WHT); these outputs go to the other two resistors. The ground input to the speed control relay is yellow (labeled YEL). If relay B is turned on, it doesn't matter if the resistors and associated relays are on, as they are bypassed, but the speed control relay should be open, so as not to steal power from the motor.
All this means is that in reverse mode, at least one resistor is in series with the motor to slow it down. The other two resistors can increase the speed, or slow it some, giving a total of 5 speeds.

[RP#62]

Well, the top of his diagram is cut off so the label is gone, but if you examine the full schematic, Starter Relay A switches battery (+) to Starter relay B, and also to Power Control relays 1 and 2 and also to one of the resistors (rightmost on the diagram), the other side of which goes to the motor (+). Power control relay 1 can apply this power to the leftmost resistor, so it is parallel to the first powered resistor, and doubles the current to the motor. Power control relay 2 can apply power to the center resistor, so triples the current to the motor, because all three resistors are now in parallel, and between the relay A output and the motor (+); relay 2 must be switched off before the Speed Control relay is turned on, or you get a direct short of the power from Starter Relay A to ground, and blow that fuse. With relay 2 off and the Speed Control relay on, the center resistor is connected to ground and siphons off some of the current coming through the rightmost resistor, and maybe also the leftmost resistor, thus reducing the speed some.

Maybe I'm reading it wrong, but it looks like BB is a ground.  When Power Control Relay #2 and the Speed Limiter Relay are energized, it connects the negative side of the battery to BB and on to two of the resistors.  When Power Control Relay #1 is energized, all three resistors are given a ground.  When any of the resistors gets a ground, it puts a load in parallel with the motor.  The number of resistors getting a ground, varies the load being put in parallel with the motor.  That's what it looks like to me anyway.

-RP

For those who need pictures, look at this closeup of the diagram:

The BLK wire from relay A changes to red at the splice above the speed limiter relay, and goes to the control relays AND a resistor, while the blue wire goes to relay B. The other side of that resistor connects to another BLK wire that goes to the motor. The output of control relay 1 is also BLK, while that of relay 2 and the speed control relay are gray (labeled WHT); these outputs go to the other two resistors. The ground input to the speed control relay is yellow (labeled YEL). If relay B is turned on, it doesn't matter if the resistors and associated relays are on, as they are bypassed, but the speed control relay should be open, so as not to steal power from the motor.
All this means is that in reverse mode, at least one resistor is in series with the motor to slow it down. The other two resistors can increase the speed, or slow it some, giving a total of 5 speeds.

Gotcha - just looked at the full diagram.

-RP