D&D PDS High Speed Motor and 8:1 High Speed Gear Experiment...

[TerryH]

OK guys. Got the motor and the gears today so here goes the first post. My goal here is to increase the speed of my cart and lower the rpm's at cruising speed. Currenty, the stock motor is turning about 7000 rpm's to run 32 mph or so and obviously that is not a great idea. I'll establish a base line with the stock motor and the stock gears for us to compare to and then begin by changing the motor and then eventually changing the rear end. I bought a donor cart that I have robbed the rear end out of to simplify the process plus the original rear end in ths cart has never been just exactly right anyhow. I'll try to document all of the steps.

This will of course be done on my 2007 PDS cart with DCX 500 PDS controller, HD solenoid, 2 gauge cables, 48v using 6 Trojan 890 batteries. My rear tires are 20" tall.

Here's the motor...





The first thing I found interesting about the motor is the size of it. It's 10.5" long and it weighs 54 lbs! If I remember correctly, and I'll weigh it again when it is off the cart, my stock motor weighs 43 lbs. That is pretty significant for sure. I honestly do not know all the technical details but the guy that helped me get this motor has a friend at D&D engineering and he explained how crazy I was...I mean the intended use of the cart and they have whipped up something for me. I thought it interesting that most of the tag on the motor is blank. The tag says it's an ES-76-51 which I don't see on their website, but if I understand correctly it should produce about 12 hp and around 80 ft/lbs of torque with my controller etc...



My invoice from D&D says what was shipped is 1-Engineering Dept. Raw Material...still looks like a motor to me.

And here's the 8:1 gear set...



I have rear end #2 back from being modified for my lowering stuff and I'll be cleaning and painting it along with changing the gears in the next few days. I did get new axle bearings and seals along with the plugs for the side of the case. Other than that, it looks good so I won't be changing anything else other than that stuff and the gears themselves. Hope to at least run the cart with the new motor this weekend so I'll report back when I have more to report.

Should be a fun experiment!!!

[Andy4639]

D&D PDS High Speed Motor and 8:1 High Speed Gear Experiment...

Terry I hope you can get what you want out of this setup. I'm wanting to hear all about it because I want to build a speedster for the beach for next summer. Is this cart running the speed senor? The new motor looks as though it's not. + you having a 500amp Alltrax in it.

A few ?'s
Did D&D give you any RPM #'s are speeds to stay under?

If you got a high speed motor with high speed gears want this mean it will take more RPM's to get moving which in return make the cart run higher RPM's to maintane a steady speed?
I'm just thinking out loud here. I hope you prove me wrong because then I know how to go on mine.
Good luck and look forward to the out come.

[gornoman]

Good luck, Terry. Keeping track of THIS one.

[scottyb]

I want a full report on my desk one morning

[TerryH]

Originally Posted by Andy4639

. Is this cart running the speed senor?

No. The motor has the harness but I will not be using the speed sensor or any regen.

Did D&D give you any RPM #'s are speeds to stay under?

They say that they would like to see me not exceed 6000 rpms for a sustained period of time.

If you got a high speed motor with high speed gears want this mean it will take more RPM's to get moving which in return make the cart run higher RPM's to maintane a steady speed?

No,not really. The rpm is the rpm. It will take more torque at a lower rpm to move the cart. Getting the cart going with the higher gear is all about the torque of the motor not the rpms. The higher gear will in fact allow the cart to go faster at a lower rpm. With the stock gear the motor turns 12.44 times for every time the tires turn once. That will go down to the motor only turning 8 times for every 1 time that the tires turn with the new gear set so the rpm will go down but it will take more torque to make the cart move..

Here are the numbers from the speed calculator...

RPM/Gear/Tire Dia./Speed
6000 12.44 20" 29 mph
6000 8.1 20" 44 mph

4000 12.44 20" 19 mph
4000 8.1 20" 29 mph

This is truly the goal here, for the cart to be able to run a steady 30-35 mph at around 4000-5000 rpm instead of the 6000-7000 that is required with the stock gear. The eventual top speed of the cart will also go up because the motor will most likely turn well over 6000 rpms but it just can't be run wide open all the time. No motor will live very long at those rpms.

This is all part of this being an "experiment." It all comes down to this: Does the motor/controller/battery combination produce enough torque to pull the cart out of the hole and up to cruising speed quickly enough to make me happy with the 8.1 gears and does the combination produce enough horsepower to push the cart up to the maximum rpm of the motor without it taking 5 miles to get there? That is the question.

[TerryH]

Originally Posted by scottyb

I want a full report on my desk one morning

Yes sir. Roger wilco. I'm glad you said "one" morning and not in the morning.

[TerryH]

I forgot to mention another interesting thing that I noticed on this particular motor. The tag says that the insulation is rated "Class H". The NEMA standard says that a Class H insulation rating means that the internal operating temperture of the motor should not exceed 180 degrees C which is 356 degrees F! That's hot!! I would certainly hope that it would never approach that but nice to know that it is rated that high anyway. I do have a motor temp probe for my dash readout so I'll be monitoring that as I test.

[scottyb]

Which field map did Vic suggest for this motor?
Certainly you will not be running the stock Alltrax DCX map?

[TerryH]

Originally Posted by scottyb

Which field map did Vic suggest for this motor?
Certainly you will not be running the stock Alltrax DCX map?

They told me map 4 but I am supposed to call them once I get everything going to get some tuning advice.

[bokeasmowl]

DnD sure makes some quality motors, I think you'll be more than pleased with the performance.