4QD controller for interurban

[one_inch_railroad]

Hi guys,

After reading quite a few posts on motor controllers, it seems the general consensus on a good choice for motor controllers is from 4QD. They really have an informative website. I will be re wiring a one inch interurban for a friend of mine, he had a controller and everything before but someone put metal control box across the terminals of the battery and shorted it out. Someone else said they could fix it but disappeared with the controller never to return. Before it only had a 3 speed control and was either slow, med, or high speed. I know a little about electronics and am learning more all the time and we decided we wanted to use a PMW controller to give it variable speed. I bough a motor controller kit that is good for 50 amps, but am not sure if that will be enough. It also doesn't have any means for reversing the motors. There are four motors, and the two motors on each truck spin opposite directions. Which 4QD controller should I get ? Would it be possible to connect all 4 motors using one controller and have 2 of them spin one direction while the other two turn in the opposite direction, then reverse direction and have them all spin the opposite direction of before. Do these controllers come with a control box or do you make it yourself ? I would also be interested in getting the DMR 203 radio control module.

I would be really grateful if someone could point me in the right direction

one_inch_railroad

[kc6uvm]

One-inch,

First of all, welcome.

Next, take a deep breath and before you go out and spend any more money then you already have, figure out what type of motors you have. Are the motors shunt/field wound, permenant magnet or? Most motors have a plate that specifies the basics. The voltage, current draw, a model number, a brand.... You might find the spec.s online when you know what you have.

Knowing the motor spec.s will help you select the type of motor controller. Some controllers are designed for a specific type of motor or motors and voltage.

4QD is a reputible motor controller. I'm using a Curtis in one of my projects.

There are four motors, and the two motors on each truck spin opposite directions.

Without looking at your interuban, I can only guess at the above. One thought is the two motors in each truck are wired in series and backwards to each other. You didn't specify the voltage. Is it 24V?

[one_inch_railroad]

Yes, unfortunately not knowing the motor specifics is what I was having a hard time with as well. He bought the interurban from a gentleman in california in the 70's I believe. Consequently the motors he used are quite old and the company that manufactured them is no longer in business. The specs on the motor plate state it is from "Hathaway Instruments Inc P/N: 9925002 DPC 801148-001 Rev. G 24V DC 5000RPM" I tried googling it to no avail. It doesn't say the motors current draw, and I cant find out what type of motor it is ie: permanent magnet vs shunt/field wound. Would it help if I posted some pictures?

Thanks

[David_T]

How many wires on one of the motors? 2 wires is a permanent magnet style. It should attract your steel tools. Four wire could be either of the other two types.
Study the heavy battery wires. How they wired to the batteries should help figure what voltage is being used.

[kc6uvm]

Back in the early '80s, I bought 24V Westinghouse motors from Koster (now CannonBall and further divided into MDM Locomotive Works) that used to be surplus aircraft engine starters rewound for use in his 1.5" engines. In Koster's design, the motors fit in-between the wheels and against the axle. I used the motors for testing a solid state motor controller chip my advisor at Cal Poly Pomona gave me to use. Considering the cost of some types of DC motors back then, the builder of your interurban could have used surplus motors which may or may not be replaceable if problems develop with the motors.

You could post pictures, someone might know what you have. Other thought, is there a club and people that you trust nearby you could take your interurban to for help or advice? What size controller are others using with an engine of similar size?

A further thought on selecting a motor controller: You might also look for a horsepower (HP) rating on your motors. 1 HP = 746 Watts. And if my memory serves me right: Watts = V * I for DC power. Or the Amperage (I) is Watts/V.

Since you have four motors, multiply the motors' power rating by 4 and you might be able to research motor controllers by the total horsepower.
Or, if you can figure out the maximum current draw for each motor from its HP rating, you might figure out if the controller kit you have is adequate.

I hope I've been a help and haven't confused you much.

[one_inch_railroad]

Thanks for the help guys, they are 24 Volt motors and are permanent magnet motors. The pieces of the puzzle are starting to come together.

[ccvstmr]

One Inch...

Some other ideas to "show and tell" as you continue to piece this puzzle together...

1) are the motors wired in series or parallel? You noted the motors are perm. magnet (2 wire). Therefore, if one motor on each truck runs opposite the other...sounds like a wiring issue. Mark the wires before disassembling so you can return to that point if needed.

2) controller sizing? 4QD and Curtis are the (2) controller names that come up most often. Other controllers include golf cart technology. I believe 4QD is in England, but they are quite familiar with the 1.5" railroad hobby applications. Talk to them. Current levels needed to start a DC drive system are quite high. You may need to oversize the controller just to handle the starting current. Note: before AC technology was refined for the industrial world and the railroads, the old fashioned DC drives on real locomotives had "short time ratings". In other words, they could over drive the motors for short time periods before backing off on the throttle. Higher "loads" meant higher motor currents. The enemy here was heat.

Hope this helps. Carl B.

[Oilcan]

One-inch:

We just toasted our 4QD-Pro120 hauling seven cars on a sunny day (4 motors running 24V). Come to find out, those boards are a little ticklish about heat build-up. Several others fried theirs too. So, please, make sure you dissipate the heat! The stock board arrangement needs some help in this area. We've replaced ours with a Kelly controller, but I can't tell you with certainty that the Kelly is better than the 4QD until we put some more hours on the rig.

I'll be curious to hear what you come up with.

Neil

[one_inch_railroad]

https://www.youtube.com/v/Mzih4wSmJQQ?autoplay=1


After finishing off a bunch of other projects on the old to do list I finally completed my friends one inch scale interurban. It was built by Steve Easlon sometime in the 80's.

The car hasn't run in over 17 years. Someone placed the controller box ( metal ) across the terminals of the battery. As you can image there was probably lots of sparks. The original controller only had 3 buttons which corresponded to slow medium and fast speed. From what I am told there was no ramping circuit so the speed/power changes were pretty abrupt.

With the old system the batteries were carried behind the interurban in a gondola car. This left barely any room for the person riding in the gondola. Also interurbans never pulled gondola cars. Now the car can be run on its own or you can ride behind it and still run it with the R/C controls.

I was originally going to use a 4QD motor controller but I ultimately went with the Dimension Engineering Sabertooth 2x60. I know its overkill for a one inch interurban but I've heard lots of stories of people burning up their motor controllers so I thought I would some breathing room there. The motor controller receives signals from the R/C receiver and turns them into PWM signals it feeds to the motors.

For the record any whining/grinding noise you hear is coming from the bull gears of the motors rubbing against the there frames/mechanical noise. The Sabertooth 2x60's transistors are switched at ultrasonic speeds (24kHz) so they don't make that whining noise some other PWM controllers do.

The R/C radio transmitter/receiver combo is a 2.4GHz spread spectrum Futaba system. I got one that is used for model aircraft as they seem to cost more (better quality) and I figure the range will be better than ones used for cars. Both the receiver and the motor controller have built in fail safes in case they loose the signal. The radio transmitter and receiver are electronically paired to each other at the factory. The 2.4GHz spread spectrum radios are virtually immune to interference and noise. I went 5 blocks away doing a range check by turning the station board lights on and off. It worked great. Even when I had my hand over the antenna from 5 blocks away. I did a test and turned off the the transmitter while the interurban was moving. The car immediately stopped.

I don't plan on running it from far away. The rule is someone is always riding behind the interurban in a riding car or its always in line of site. This is being run on a private track and I would never bring it to a club track, because I know R/C is still a touchy subject in the hobby. And I understand peoples concerns considering how much time, energy and money they have invested in their equipment. Perhaps as time goes on and the 2.4GHz systems prove themselves they will become more accepted in the hobby.

There are two ways I can use the throttle. If connected to channel two of the receiver you use the left joystick on the transmitter which is normally used for the throttle on R/C aircraft. There are 13 notches or detents for going forward and 13 for going in reverse. Upon startup of the system the motor controller auto calibrates itself. So if you start with the stick 1/4 of the way up from the bottom that will be the zero point. So you will have 3/4's of the notches for going forward and only 1/4 for going backwards. This will give you more notches for forward speed control. This can also be used to limit backup speed.

If however the motor controller is hooked up to channel 3 on the receiver the right stick which is normally used for the elevator control on airplanes is used. The right stick has not detents and is spring loaded to return to center. In this way it acts a deadman's pedal so to speak. This is the one that will be used if guests or children run the car as an added safety measure.

The only lights hooked up right now is the station name board. Inside the car I have used LED strip lights, the marker lights will have LED's in them. The headlight will have off, dim, and bright. All the lights except the headlight will be powered by LED's and can be turned on and off remotely and independently using R/C relays. They also have individual PWM circuits to independently dim the lights.

Other things that would be cool to add at a later time would be a real time FPV camera that broadcasts to your TV so I could control it from inside the house and see whats ahead from the first person view. That would really freak some people out!

But being more realistic I would like to add a phoenix sound system.

http://www.phoenixsound.com/library/other/trolley.htm

[chooch]

One inch railroad--no name.
If you go to the Yahoo group "livediesel" you might also get some info as you mentioned Koster. He is still around and often posts on that group. Of course you have to join same as here.
chooch

[chooch]

1-inch-railroad,
Just thinking. Is it possible one of the trucks has been turned completely around. I had a G scale and one of my 1-1/2 inch locos that it happened to--trucks turned in opposite directions. A tug of war and the larger loco won.
chooch

[one_inch_railroad]

Chooch,

Thanks for responding but who is Koster? Also why would you say one of the trucks may be turned around. Is there something that would lead you to believe that. The first time I hooked it up it did that. It would sort of go a few inches one way and then a few inches the other way. So I switched one set of leads around and its fine.

Warren