Metal Transfer Cart from Buggie Parts

[kelleyb]

Hello All,

I am a Mechanical Engineer with West Salem Machinery here in beautiful (but currently raining) Oregon. I have been tasked with reproducing a transfer cart that one of our affiliates uses to move 20' to 24' steel pieces in their warehouse (it saves on the wear and tear of the overhead crane). It was peiced together using what appear to be Club Car parts, although the drive gearbox is a complete unknown.

We are going to build at least one to several of these for the other warehouses. I am fairly confident in the mechanical design (although I have some questions if I can use an h-12 axle for the gear reducer, but I will play that one by ear)!

However, I do have some questions on the electical, although I am beginning to understand a lot more from the posted schematics. I will try to post a pdf of my design schematic sometime tomorrow once I clean it up so you guys can pick it apart.

My current question is what is the ball park amperage draw of the 2 horse GE D294 motor using 36 volts? The run from batteries to the control levers is about 12', and the return to the motor is about the same, and I want to properly size the wires.

Also, where do you locate fuses and what size should they be? Having troubles deciphering that from the schematic posts.

Thanks for your help and I hope you find this an interesting build! I'll try to post pics soon :) Take care!

[scottyb]

If I am reading you right you are concerned about running the high amperage 12 ft to the F&R control . That is a legit concern. Why not design something with 2 solenoids to switch the power F&R back at the batteries and motor location without the long runs. Ps; use 4 gauge or heavier battery cable.
There are others here who can help a lot more than me but, this is what I would ask about....

I would think you could make this remote control? Will it run on track?

[gornoman]

A heavy cart might pull 250+ amps on initial startup and cruise around 40-60 amps. For your application I would use 2g high strand-count welding cable.

[roady89]

Just my opinion here. The startup amp draw will be very high. You need to use a high amp controller. Do not use a resistor style system. The risk of burning resistors is far greater. The voltage can be as little as 24 volts as long as you have available amps. You could use a 500 amp alltrax which will run on 24 volts....at 12' I would use 2 gage welding cable. The alltrax you can set a throttle up rate, you can even set braking current. A low RPM, high torque motor will help keep the amp draw down. The GE D294 is just a stock 2800 rpm motor but IMO is just to darn fast for what your planning. (but I'm not 100% sure what your doing exactly.) On a stock golf car the startup amps can be as high as 250 amps or even more I'm sure, stock controllers are usually 275 amps, you will surpass that easily if your not geared right and using that motor but like I said, I'm not 100% sure what and how heavy your peices are.


The fuse can be placed anywhere in the battery string or on either end of the string or even on the controllers B- terminal. 400 amp controller or LESS use a ANN250 bussman or Llttlefuse. 400 amp controller or MORE use a ANN400 bussman or littlefuse.

This is a basic wiring schematic that uses an Alltrax controller, PB-6 pot box for a throttle and a czonka relay. You could subsitute the manual F/R switch for a solenoid type F/R switch.

[scottyb]

. And what about a moderate voltage activated solenoid F&R?

[pggroves]

We built a couple of transfer cars for steel coils up to 30 tons.
We're currently building an exit car for slit coils up to 10 tons.
We've found utilizing batteries to power a small hydraulic unit for tractive and in our case lifting was the best way to go.
The 30 ton we built was 24v and the slit coil car we're currently constructing will be a 48v unit just for longer run times.
I'd suggest you incorporate an automatic charging system when car returns to a "home" position. We've found it best to take charging the batteries out of "human" hands.
Sounds like you are transporting long products like tubing. Our cars are used in a steel slitting and CTL operation and in support of a slitter at a tube mill.

[kelleyb]

Thanks everyone, you guys are awsome. It really helps to have some discussion so I can think about the design better (I sometimes get a little lost in the digital world....)

I looked at the Alltrax before and in this application I think it is a good idea even though the previous one doesn't have one.

I am also open to changing the motor, I'll look into it.

I also REALLY like the idea of the remote second solenoid, heck we could pay for it with copper savings!

I think I'll make up a new schematic showing those changes and we can go over them then (probably not 'till Monday!).

In the meantime, here are some pictures of the existing cart. The new one weighs about 3500# and will carry up to 1500#. Not sure of the weight of the old one but it is probably similar. Thanks again everyone, I really appreciate sharing knowledge with those that have it! (I struggle more with those who don't ) Have a great weekend!
BK

[kelleyb]

Hello again,

Hope you had a good weekend everyone. Here is the schematic I came up with based on the Alltrax schematic with plug braking. Any comments are appreciated!

Next I am revisiting the motor and drive set-up. Currently we have a GE 2 Hp at 2800 rpm going through a Spicer H-12 axle (12.44:1 ratio) and then geared down 15/60 for a final drive of about 50:1. This gives a ground speed of approximately 2.6 mph. (!Really flying!) This is about what was requested. I am open to other motors and maybe a more standard industrial gearbox if anyone has ideas of where to look. (Had a lot of trouble finding anything else that would mate to the GE 19 Spline motor, but maybe with a different motor....)

I'll shoot Alltrax an e-mail as well and see what they recommend. Thanks again!

BK

[kelleyb]

OK, screwed up the upload! Here is the schematic! I had to do it as a .jpg since the .pdf was too big. Can e-mail one if anyone wants to look at it in a better version. Thanks!
BK