Two restorations

We Can Rebuild Them, We Have The Technology.

Two restorations

Postby Robaroni » Wed May 22, 2013 3:01 pm

Well, I'm excited to set up my summer projects, A home made windmill and microhydro for my off grid alternate energy system, a root cellar, lathe DRO, and hopefully I'll be able to restore my E20 and E15 from the tractors and attachments I've been gathering. Right now I have about two or three that can be restored with the usual problems (corroded frame parts, bad electrics, seats. etc.)
I was going to build a plasma cutter but I don't think I'll have time so I'll have to plasma by hand or templates.

A couple of question for the pros here that have been this route. The yellow paint, I see you can get it in spray cans but I'd rather us quarts. I can go my local HD or ACE and have them mix the paint for me in quarts. What are most of you using? Enamels, acrylics,? Also I want to spay it with HVLP. It seems Mark Frerking has it down so any pointers would be helpful. Does anyone have a paint value that can be plugged in to get the right mix?

I'll also try to get to the charge controller and motor controller designs as I've been gathering parts for those as well.

Here's a sample of my winter project (took 4 mos. to design!) that is at the labs of Elektor Magazine now, the circuits have a lot in common with my designs for the ET using SMPS (switch mode power supplies), MOSFETS and charge controllers for the caps.

It runs on super capacitors that charge in two to three minutes and run the amp for about two hours. If you use it for an hour, like I do in my workouts, it charges in about 35 seconds to full. For those of your who don't know about super caps, they can be charged thousands of times, left sitting dead for years and come back to life in a few minutes.

Thanks for the help,
Rob
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Re: Two restorations

Postby roberttroll » Wed May 22, 2013 4:00 pm

As far as paint goes, two years ago i had a clean piece of the yellow tested.. The resulting color mix formula is this:

This is their XORust type paint
Base - XO-D
AX - 41 Shots (a bright yellow)
C - 1oz - 8 Shots (a mustard tint)
I - 1 Shot +1 Half Shot (a darkener)

Around $9 a quart and matches the original colors.


Looking forward to seeing your controller designs. I am installing version 2 of my curtis, and already have version 3 in mind.

And real nice work there...
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Re: Two restorations

Postby Robaroni » Wed May 22, 2013 5:52 pm

Robert,
Thanks for the info, is that ACE, Home Depot or both?

I've heard good things about the Curtis controllers. If it takes too long to design the battery charger electronics I might simply get one but I will likely try my hand it at first! The battery charger shouldn't be too difficult, the challenge is making a design that folks can put together. Once you start getting into some of these leadless QFN packages (like the chips in the design above with its 7 or 8 IC's) things get real nasty and you need special equipment. I'd like to do as much of the design as possible with through hole devices but, on the other side, I like to make small boards to save money in materials and board house costs so I'll have to try and balance the final design.

Best,
Rob
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Re: Two restorations

Postby roberttroll » Wed May 22, 2013 6:34 pm

Sorry - that is for the true value XO rust line.

The biggest issue i have with getting the Curtis to work is coming up with a design that is fail-safe. That is finding a way that the armature will never receive power if the field does not. As it stands now, in my design, there is a possibility of that happening if the relay that i am using fails in the closed position. So i have put in idiot lights. Now i have asked quite a few people the question "what are the chances that a normally open relay fails in the closed position." I kind of get stares and not much in the way of an answer. I just want something that is 99.999%. My design number 3, uses STDP relays. Those are impossible to find in stock in 36v. So i have to use 24v ones which i am not crazy about......

I was also reminded that there is nothing in the original GE design that prevents the scenario (armature power - field no power). So it most likely inst a catastrophic situation.
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Re: Two restorations

Postby mfrerking » Wed May 22, 2013 6:48 pm

Rob,

I have found that you get what you pay for when it comes to paint. The local hardware store enamels can give a decent covering. But, they will fade sooner and are not as tough as those purchased from automotive paint suppliers or an O'Reilys paint department.

My local O'Reily's has two and three part paints. They can also load the paint into rattle cans if you want.

There is a rather significant difference in the price as well. Hardware store enamels are $10 a quart verses $40 from automotive paint suppliers.

If you are starting out with all new metal, powder coating is the way to go if you can find someone willing to do it for a reasonable cost. Most folks are doing restorations. So, spray applications generally will give the best results.

I have been tempted to try some of Tractor Supply's paint products. They have an additional hardener that can be added.

As far as controllers, the regin ability of the 4QD units appeal to me. Plan to try one on this next build...
Last edited by mfrerking on Wed May 22, 2013 7:55 pm, edited 1 time in total.
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Re: Two restorations

Postby roberttroll » Wed May 22, 2013 7:33 pm

Mark -

I agree on the paint.

Hopefully we can talk a bit about the 4QD at the Vermont show. My simple analog setup would work just fine with the 4qd. I just wasn't sure about their product as i couldn't find much on it over here. I have no allegiance to any particular controller. Just went with what was cheapest and most readily available for me at the time.
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Re: Two restorations

Postby Robaroni » Wed May 22, 2013 8:12 pm

roberttroll wrote:Sorry - that is for the true value XO rust line.

The biggest issue i have with getting the Curtis to work is coming up with a design that is fail-safe. That is finding a way that the armature will never receive power if the field does not. As it stands now, in my design, there is a possibility of that happening if the relay that i am using fails in the closed position. So i have put in idiot lights. Now i have asked quite a few people the question "what are the chances that a normally open relay fails in the closed position." I kind of get stares and not much in the way of an answer. I just want something that is 99.999%. My design number 3, uses STDP relays. Those are impossible to find in stock in 36v. So i have to use 24v ones which i am not crazy about......

I was also reminded that there is nothing in the original GE design that prevents the scenario (armature power - field no power). So it most likely inst a catastrophic situation.


Mark, thanks for the great info! I suspect I'm kinda like you, if I'm going to do it I'm going to do it the best I can and if that means a few more bucks for paint, so be it. I have a friend, don't we all! who fixes everything with bailing wire and duct tape. the problem is that he's always fixing the same things over and over..... He always give me a hard time about my thoroughness but I usually fix things once.

Robert,
Thanks for the update, I'll have to do some research!

On relays: Actually locking in the closed position is quite common. Here's why. Relay pit if there's the slightest impurities on the contacts, dust, oil, etc. And when that happens they can 'lock' in the on position because the pits on each contact 'lock' to each other, so you're right to be concerned. The other thing about relays is that if they are adjusted correctly there is something called 'follow' that must take place. Follow happens when the contacts meet and continue for a short period so as too clean the carbon or other impurity off. So check your relay's to make sure they have follow as it will extend their life considerably.

Also, I'm wondering if the Curtis has a lead extended out so that you can shut it off automatically if the state is wrong just for conditions like you had or something catastrophic occurs? this may be a way to reslove your problem using a simple sensing circuit.

Best,
Rob
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Re: Two restorations

Postby roberttroll » Wed May 22, 2013 9:03 pm

Robaroni wrote:On relays: Actually locking in the closed position is quite common. Here's why. Relay pit if there's the slightest impurities on the contacts, dust, oil, etc. And when that happens they can 'lock' in the on position because the pits on each contact 'lock' to each other, so you're right to be concerned. The other thing about relays is that if they are adjusted correctly there is something called 'follow' that must take place. Follow happens when the contacts meet and continue for a short period so as too clean the carbon or other impurity off. So check your relay's to make sure they have follow as it will extend their life considerably.

Also, I'm wondering if the Curtis has a lead extended out so that you can shut it off automatically if the state is wrong just for conditions like you had or something catastrophic occurs? this may be a way to reslove your problem using a simple sensing circuit.

Best,
Rob


The curtis 1204 is made for a PM or Series wound motor. It does not know about the field. That is the issue. How to handle the field safely. The curtis has a simple on/off sensor which is what i am using the relay with. Power for that runs through all of the usual tractor safety's. So the whole thing shuts down if any of the usual safety switches are triggered. I am reversing my elec-trak by simply reversing the field. Works great and has been flawless in the past year that i have used it. It does plug braking, which has not been an issue for me as the high pedal disable feature shuts off the armature power until the throttle is brought back to zero. This effectively slows down the motor before allowing it to reverse, although you can still plug it if you are rolling. In practice the setup behaves very much like the stock control setup.

The 4QD is also a PM motor controller. So the same field issue would apply. However the 4QD has built in elegant (ramps power down) armature reversing. To use it in the ET you would simply just need to make sure the field always has 36v.

The alltrax made for the elec-trak is a "copy" (gross oversimplification) of the curtis with a built in field sensing ckt and sends 2-3a to the field. It also elegantly reverses the motor.

If you want built in field capability, and do not want to go with the alltrax, the other option is a sepEx controller. However as it has been pointed out, the standard golf cart motor has a much larger field current then the elec-trak motor (10a plus). However there are a few guys who use them, and i would imagine putting a simple fuse on the field ckt would solve the problem. However i have just not come across a sepEx controller cheaply enough to jump on it. There are a few other issues as well.

I went with the curtis because it is as common as dirt around here and can be rebuilt for next to nothing, and i knew it could be made to work as a few people were already using them.

As far as the relay issue, the ones i am using are sealed. So i did not know think impurities are a huge concern, but they are mechanical and everything mechanical fails at one point or another. The relay contacts are rated for 10a and only switching in the MV range. I could double up on the relays which would require a double failure..... But i keep going back to how the original GE design was not this robust so i do not think that the engineers thought it was a huge issue. The motor could over-speed, and power will jump, but you jump off and it shuts down...

I hope all that makes sense. My background is not in electronics and i have learned by experimentation and pulling things apart.
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Re: Two restorations

Postby Robaroni » Thu May 23, 2013 12:12 pm

roberttroll wrote:I hope all that makes sense. My background is not in electronics and i have learned by experimentation and pulling things apart.



I think most of us started this way. I used to collect tubes from broken TV's left out for the trash man and when I was eight my parents asked me what I wanted for my birthday.... I told them a soldering iron, just what every worthy dismantler needs! Wow! that was sixty years ago and I still have that iron around here somewhere!
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