Not that I understood it all, but your two posts are my “Posts of the Year” nominees.
Just awesome... Keep posting. - Mark Sent from my Fuel Cell powered iPhone > On May 25, 2019, at 10:37 AM, Mr. Sharkey via EV <[email protected]> wrote: > > Glad you found it informative. > > These motors are frequently called "forklift motors", probably because, well, > they were used in forklifts... Your Siemens controller is likely a "forklift > controller", assuming that the conversion company didn't design one from > scratch and have Siemens construct it (them). It might be possible to find > more information on that unit by haunting industrial material handling > equipment sites and forums. > > It is possible that your controller also does some armature voltage control, > some sep-ex motor controller do, so that's something to keep in mind when I > go on about the armature having full battery voltage on it continuously > during operation. My controller is a dedicated design by EHV Systems > specifically for the SCT Rabbit vehicle, so obviously SCT didn't find > off-the-shelf controllers to be suitable in some way. > > It might be possible to power the motor from 12 volts directly. You would > need to identify the field wiring and disconnect it from the controller > (label things first). On my motor the fields are powered by a cable running > in the flange on the output shaft end of the motor, on a length of SO-type > rubber cord. The fields draw only about 10 amperes at 120 volts, so not much > is needed in the way of heavy wiring. The low field current is also a reason > that the controller can be much simplified, no heavy current switching > devices. > > The armature connection is two additional cables exiting the motor adjacent > to the field cable. The armature in my controller is limited to 275 amperes > at 120 volts. I don't know what the armature would draw at 12 volts, might > not be enough to draw much of a spark when connected. Because the motor has > poor locked-rotor torque, it will pull more current until it attains some > rotational speed. Idle current at 120 volts is about 10 amperes. If it looks > like it is going to try and spin up, you might give it some manual assistance > to get past that stall problem at low voltage. > > Do inspect the brushes, if you get the motor running with stuck-ish brushes, > you risk a burned commutator, particularly at higher voltage. I would check > the brushes and then move on to investigating the controller, the motor is > about the least likely reason that you get no response so far. > Glad you found it informative. > > These motors are frequently called "forklift motors", probably because, well, > they were used in forklifts... Your Siemens controller is likely a "forklift > controller", assuming that the conversion company didn't design one from > scratch and have Siemens construct it (them). It might be possible to find > more information on that unit by haunting industrial material handling > equipment sites and forums. > > It is possible that your controller also does some armature voltage control, > some sep-ex motor controller do, so that's something to keep in mind when I > go on about the armature having full battery voltage on it continuously > during operation. My controller is a dedicated design by EHV Systems > specifically for the SCT Rabbit vehicle, so obviously SCT didn't find > off-the-shelf controllers to be suitable in some way. > > It might be possible to power the motor from 12 volts directly. You would > need to identify the field wiring and disconnect it from the controller > (label things first). On my motor the fields are powered by a cable running > in the flange on the output shaft end of the motor, on a length of SO-type > rubber cord. The fields draw only about 10 amperes at 120 volts, so not much > is needed in the way of heavy wiring. The low field current is also a reason > that the controller can be much simplified, no heavy current switching > devices. > > The armature connection is two additional cables exiting the motor adjacent > to the field cable. The armature in my controller is limited to 275 amperes > at 120 volts. I don't know what the armature would draw at 12 volts, might > not be enough to draw much of a spark when connected. Because the motor has > poor locked-rotor torque, it will pull more current until it attains some > rotational speed. Idle current at 120 volts is about 10 amperes. If it looks > like it is going to try and spin up, you might give it some manual assistance > to get past that stall problem at low voltage. > > Do inspect the brushes, if you get the motor running with stuck-ish brushes, > you risk a burned commutator, particularly at higher voltage. I would check > the brushes and then move on to investigating the controller, the motor is > about the least likely reason that you get no response so far. > > If the van is limited to second gear, how is reverse accomplished? Shutting > down the motor to reverse it's rotation seems like a nightmare for an on-road > vehicle, would make parking a real hassle. Stop motor, reverse fields, > restart motor, repeat as necessary. Uhg. > > If you get it running, you might want to consider changing the transmission > setup. I use all four gears and reverse. 4th isn't useful until about 50 > MPH, but a lot will depend on your final drive ratio. Don't some (all) of the > old VW vans have reduction gearing after the differential? > > A link to my SCT Rabbit on the EV Album: http://evalbum.com/91 > > In particular, a PDF of the field and armature control circuitry in the SCT > controller, This will give a sense of how the motor expects to be supplied > with voltage: > > http://web.archive.org/web/20111109035218/http://www.mrsharkey.com/SCT/field.pdf > > At startup, K1 & K2 are energized, field gets full voltage (PWM is disabled > in controller card) the armature gets battery voltage through two paralleled > 3 ohm resistors and begins to rotate. When the controller determines that the > armature is spinning by monitoring the voltage, it pulls in K3, directly > connecting the armature to the batteries, and the PWM circuit (Darlington > transistor pair) is enabled to allow field weakening in response to > accelerator position. At this stage, the key can be released to the "run" > position. Shutdown is all relays de-energized. > > Something to consider: It would be fairly easy to design and build a > substitute controller with an Arduino, some instrumentation-grade op-amps and > a couple hundred lines of code. The days of using TTL/CMOS discrete > components to build logic and control circuits is long past. > > Overloaded yet? > > At 08:50 AM 5/25/2019, you wrote: > > >> Awesome, thanks so much for the information. This is a great start towards >> making this thing work. When I was in college, one of my computer science >> professors explained that the people in the factory put the magic smoke into >> the electronic components, and it is our job not to let the magic smoke out. >> I have taken this to heart when working on electric stuff like this which I >> know very very little about. Thus I am unwilling to just put voltage to a >> component like the motor and see what happens. Normally, when I go to work >> on something I have a massive technical library to draw upon, but in this >> case, I am starting out in the dark and this has shined some light. >> >> On the operational characteristics of this motor, by the field having full >> voltage at stop (or just more voltage than the armature), it overpowers the >> armature and creates drag buy forcing the system to generate electricity, >> and when the armature has more voltage it uses the battery power to turn. >> Is this correct? Not that it necessarily helps in getting it running, but I >> like to know how/why things function. >> >> I turned the key on, and to the start position a couple times, but I got >> nothing to indicate than any electrons were flowing anywhere in the system. >> I figured that the start position was just a relic of a standard ignition >> switch. I did not have a 12v battery hooked up, which is likely one reason >> things didn't work. I had scavenged every easy to grab battery around the >> shop, and I had 10 12v and 2 6v strung together in the battery tray, and >> none left over for the vehicle. I will scrounge up a couple more batteries >> to make this work. >> >> I tried to take the cover off the motor, but to didn't want to pop right >> off. I will play around with that some more. The brushes are not stuck to >> the armature, as I have made it turn manually, but I don't know that they >> slide freely in their housings. >> >> One thing that I read about this specific system is that it has regenerative >> braking from 43mph down to 30mph, and another source said that it has >> regenerative braking down to 0mph. The top speed is 43mph. Either way, it >> is not all that important, as it works one way or the other. The brake pads >> show very little wear, but the vehicle only has 11,000 miles on it. An >> interesting thing with it is that there is no vacuum brake booster like is >> seen on every other VW with disc brakes. That makes more sense with the >> regenerative braking. >> >> I will play around with this more next week and report back on my progress. >> >> >> -- >> Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com/ >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > > ____________________________________________________________ > US MD: "I Beg Americans To Throw Out This Veg Now" > unhealthpublications.com > http://thirdpartyoffers.juno.com/TGL3131/5ce97d698b9c27d61139ast01duc > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
