Current draw on the starter?

[John Schmidt]

Anyone have an idea as to the amps the starter pulls when engaged? If memory serves, the formula is watts/volts=amps, I just don't know the watts of the motor, there's no markings on it and I can't find anything in the Gold Wing manual. Any suggestions or knowledge of what the various values might be. Obviously the VDC is 12vdc +/-, but need one of the other values...watts or amps. I'm tying to determine if a large variable resistor would work in place of the system's resistor pack which appears to be used to control the reverse speed. I would think that's necessary, nobody wants to be  backing out of a parking spot at 20mph. 

[98valk]

I checked all of my reference materials and this is all I could find.

starter relay regulator current 0.7 - 1.0 A

from '89 goldwing manual

[WintrSol]

I have one of these: https://www.newark.com/c/test-measurement/multimeters-clamp-meters/clamp-meters?brand=tenma
It's the model 7228, which has served me well. I can't swear to the accuracy, but you just need a ball-park figure. Also, I doubt you would need the 1000A scale.

[Bagger John - #3785]

1HP = 746 watts.

The GL1500 series starter motor is a bit smaller than a Spike's 2HP unit - roughly the same size as one of their 1.4HP models. For purposes of this thread we'll say 1.5HP.

That equates to right around 1100w. Divide that by 12(v) and you get 92A. I've seen 100A mentioned when this motor comes up in discussion.

FWIW.

[Bagger John - #3785]

I have one of these: https://www.newark.com/c/test-measurement/multimeters-clamp-meters/clamp-meters?brand=tenma
It's the model 7228, which has served me well. I can't swear to the accuracy, but you just need a ball-park figure. Also, I doubt you would need the 1000A scale.

Compared to what my Tektronix stuff fetches (even used) that Tenma unit looks to be a good bargain.

[John Schmidt]

1HP = 746 watts.

The GL1500 series starter motor is a bit smaller than a Spike's 2HP unit - roughly the same size as one of their 1.4HP models. For purposes of this thread we'll say 1.5HP.

That equates to right around 1100w. Divide that by 12(v) and you get 92A. I've seen 100A mentioned when this motor comes up in discussion.

FWIW.

John, I'm thinking that 92A isn't far off. I have a reason for all this and it's due to the Wing motor I plan to install...comes with reverse. I figure the wattage might be a bit higher when the reverse is kicked in, the voltage applied goes through a resister pack that slows the motor to a manageable rate/speed for backing up. So, instead of using a resistor pack I'm debating using a pot large enough to gain greater variation(and space) in voltage used. Re. space, the resistor pack isn't small, however a pot large enough to handle the job may well be quite large as well. Honda uses a large number of inputs to the Reverse Control Unit before it ever allows the reverse to be put in motion. I don't plan on that, just a couple extra relays that will make certain all is correct prior to activating; kickstand up(not an issue on a trike), start relay is out of the circuit, reverse relay is in, reverse indicator light is on. It's going to be a long winter. 

[WintrSol]

Assuming that, with the resistor pack, that current is about 1/2 starting current, that will be one HUGE potentiometer! All the more reason to measure it first. Perhaps some kind of electronic motor controller would create less heat, by chopping the current on/off, instead of just getting hot.

[John Schmidt]

This link will give you an idea of how the resistor pack is constructed, note the cooling fins. There's three resistors inside, per the schematic it appears two are used initially and a third is thrown into the loop if an overspeed is detected. Scroll down in the link to get to the item I bought, I plan to hook it up to the starter while still sitting on my hydraulic table. First I'll run the starter motor without the reverse engaged. Next I'll engage the reverse to see what effect the resistor pack has on starter motor speed. I should be able to test the resistance of each resistor in the circuit and as a total of all three.

https://www.ebay.com/itm/275400196053

[WintrSol]

Running without a load may show the motor running somewhat slower, but it is the load that draws the current that makes the resistors work. The resistor values will tell you how much power they are turning to heat, if you can measure the current while it is moving the bike. It will, of course, draw more current backing up a grade than on a level lot, but I'd still start out level. A good motor controller turns the current on and off at a fairly high rate, so you don't generate a lot of heat, and controlling speed is easier. High Wattage rheostats are also hard to find.

[Bagger John - #3785]

A good motor controller turns the current on and off at a fairly high rate, so you don't generate a lot of heat, and controlling speed is easier.

A thyristor-based PWM design would be ideal for this application, but I'll bet you a commercially available version is gonna co$t.

[John Schmidt]

John, I'm not very familiar with the type you mentioned, can you expand on it a bit? Explain how it functions, etc. It would be kinda nice to be able to "dial in" the reverse speed one wants if possible.

[Bagger John - #3785]

John, I'm not very familiar with the type you mentioned, can you expand on it a bit? Explain how it functions, etc. It would be kinda nice to be able to "dial in" the reverse speed one wants if possible.

Think of a regulator in terms of what it supplies to a load - a given percentage of available power, from 0 to 100%.

There are three ways to accomplish this. One is to vary the applied voltage, while keeping the current constant. Another is varying current while keeping voltage constant. (EEs and similar designers use these two all the time - a good example is a variable output bench top power supply. I have a couple of 0-15V/0-50A Astrons to my left as I type this, and an operator can adjust voltage and current output as required.)

The third way to control power to a load is to manage the duty cycle of the applied energy. Voltage and current remain constant but you adjust the power factor via pulse-width modulation. This technique is widely used in such things as automotive LED headlights, including our Daymakers.

If you search the forum for threads from me on Daymaker noise generation (and suppressive measures), I illustrated the waveforms such controllers employ.

With large loads (high amperage) comes the need for switching devices that can handle the current without dissipating a lot of energy as heat. Thyristors and similar high-current devices are ideal for this sort of application. The downside is they're physically large and do require a bit of heat sinking.