PDS not fast

kojo · 11-15-2014, 01:30 PM

A friend of mine is working on a guy's Ezgo PDS cart for him and put a what is supposed to be a torque motor in it and a Alltrax DCX 400PDS. The guy that owns the cart also has 8:1 gears in it. He had the stock motor along w/ the gears and 400 Alltrax and the motor went south on him and took the 400 with it. I don't know where the motor came from, but it's red if that helps any. He got a new 400 also with a White Rodgers solenoid. Anyway, I was over at my buddy's house last night and when he got everything working he took it for a test drive and the cart wouldn't go but about 12mph maybe 15mph with a tailwind. The owner told my buddy it was going about 31mph before the stock motor went out. I know a torque motor wouldn't be as fast on top end but with the 8:1 gears he should be getting a little faster than that though I would think. Anybody got any advice he could try, to see if something's amiss. Oh, and it's 48v, with Trojan 860's in it and they read around 50.4v. Could it be the solenoid? My buddy didn't know if the guy changed the solenoid or not after the stock motor went out. The owner tried working on it himself before giving it to my buddy to try and fix and we don't think he has something right. I mean the owner said something about the lights being too dim and come to find out, he had both wires going to two pos. posts.

So any help would be great guys, I'll probably go over this evening to his house and try and see what we can find out. Thanks fellows.

scottyb · 11-15-2014, 02:22 PM

Quote:

Originally Posted by kojo

A friend of mine is working on a guy's Ezgo PDS cart for him and put a what is supposed to be a torque motor in it and a Alltrax DCX 400PDS. The guy that owns the cart also has 8:1 gears in it. He had the stock motor along w/ the gears and 400 Alltrax and the motor went south on him and took the 400 with it. I don't know where the motor came from, but it's red if that helps any. He got a new 400 also with a White Rodgers solenoid. Anyway, I was over at my buddy's house last night and when he got everything working he took it for a test drive and the cart wouldn't go but about 12mph maybe 15mph with a tailwind. The owner told my buddy it was going about 31mph before the stock motor went out. I know a torque motor wouldn't be as fast on top end but with the 8:1 gears he should be getting a little faster than that though I would think. Anybody got any advice he could try, to see if something's amiss. Oh, and it's 48v, with Trojan 860's in it and they read around 50.4v. Could it be the solenoid? My buddy didn't know if the guy changed the solenoid or not after the stock motor went out. The owner tried working on it himself before giving it to my buddy to try and fix and we don't think he has something right. I mean the owner said something about the lights being too dim and come to find out, he had both wires going to two pos. posts.

So any help would be great guys, I'll probably go over this evening to his house and try and see what we can find out. Thanks fellows.

Funny thing about this is that on 48v, the stock motor would give 28-30 mph with the stock 12.4:1 gears.

kojo · 11-15-2014, 02:41 PM

Scotty, just talked with my buddy and he said that the owner said it was going 34mph before motor went, so my bad.

But I'm with you Scotty, with the 8:1's and stock motor, I think it should be going a little faster than 34mph.

JohnnieB · 11-15-2014, 04:11 PM

No mention about tire height, but with stock height tires and 8:1 gears, 34MPH is slow for 48V on a stock motor since the motor is only turning about 5100 RPM and when I was running a stock PDS motor with a DCX400 at 42V I could spin the motor at about 7000RPM on level ground.

The mathematical top speed for a stock motor on stock height tires and 8:1 gear at 48V would be roughly 47 MPH, but the gears will knock the torque down by about 36%, so motor will run out of high end torque long before the cart gets to that speed.

Are you sure the red colored replacement motor is a Sepex motor?

Attached are end views of a series and a sepex motor. The first photo is a series, note the field windings are thick and few while the field windings on a sepex (second photo) are thin and many.

Also, how many times the the LED flash green before is comes on steady? (Four flashes for an ITS throttle)

JohnnieB · 11-15-2014, 04:17 PM

Also, check which field map is loaded in the DCX controller, it has to match the motor (whatever it is), but I don't think that is what is holding it back.

kojo · 11-15-2014, 05:11 PM

JohnnieB, it has 23" tires and I'm pretty sure it's a sepex motor. Can you put a series motor in a PDAS cart and run it w/o changing anything else? And, would that cause it to run so slow? The owner didn't give my buddy another field map to put in it so, it has the #4 map in it now. My buddy went in the program last night and checked some stuff in it and changed a couple of things.

sportcoupe · 11-15-2014, 05:22 PM

Once you add gears (or larger tires) on a stock motor it has much less of a change of obtaining max rpm so the actual speed will be less then the theoretical speed.

This doesn't explain why the poster is only seeing 12 mph though with a Alltrax DCX. That controller should make 24+ mph easily at 48v on stock motor as Scotty mentioned. Add 8:1 gears and it will go a bit faster but will never obtain it's stock tire rpm and calculated speed due to the low power output.

sportcoupe · 11-15-2014, 05:30 PM

I didn't see the post with tire size till now.

23" tires AND 8:1 gears is crazy (IMO).

A stock PDS with 18" tires does 5700 rpm at 24 mph with 12:1 gears.

Calculated mph of a 23" tire and 8:1 gears is 49 mph at the same 5700 rpm, which you will never reach because the stock motor is too weak.

When you put 8:1 gears AND 23" tires it is the same thing as putting 34-35" tires on a stock 12:1 geared cart. Performance will suffer greatly. I doubt the cart can climb a curb from a dead stop.

kojo · 11-15-2014, 05:45 PM

Remember that he doesn't even have the stock motor anymore, it went out with him. He's got some motor that's red from somewhere. Supposed to be a torque motor that he has now. Which definitely doesn't explain why it's only going around 12mph. At least that's what it feels like to me.

sportcoupe · 11-15-2014, 06:23 PM

I've never heard of a sepex motor that is wound so low as it would only do 12 mph on 35" tires (equivalent of 23's and 8:1 gears).

No matter what motor you have, it's only turning 1400 rpm at 12 mph in that cart. That is unrealistic. Something else is missing.

11-15-2014, 01:30 PM	#1
kojo Gone Wild Join Date: Oct 2013 Location: Aynor, South Carolina Posts: 552	PDS not fast A friend of mine is working on a guy's Ezgo PDS cart for him and put a what is supposed to be a torque motor in it and a Alltrax DCX 400PDS. The guy that owns the cart also has 8:1 gears in it. He had the stock motor along w/ the gears and 400 Alltrax and the motor went south on him and took the 400 with it. I don't know where the motor came from, but it's red if that helps any. He got a new 400 also with a White Rodgers solenoid. Anyway, I was over at my buddy's house last night and when he got everything working he took it for a test drive and the cart wouldn't go but about 12mph maybe 15mph with a tailwind. The owner told my buddy it was going about 31mph before the stock motor went out. I know a torque motor wouldn't be as fast on top end but with the 8:1 gears he should be getting a little faster than that though I would think. Anybody got any advice he could try, to see if something's amiss. Oh, and it's 48v, with Trojan 860's in it and they read around 50.4v. Could it be the solenoid? My buddy didn't know if the guy changed the solenoid or not after the stock motor went out. The owner tried working on it himself before giving it to my buddy to try and fix and we don't think he has something right. I mean the owner said something about the lights being too dim and come to find out, he had both wires going to two pos. posts. So any help would be great guys, I'll probably go over this evening to his house and try and see what we can find out. Thanks fellows.

11-15-2014, 02:41 PM	#3
kojo Gone Wild Join Date: Oct 2013 Location: Aynor, South Carolina Posts: 552	Re: PDS not fast Scotty, just talked with my buddy and he said that the owner said it was going 34mph before motor went, so my bad. But I'm with you Scotty, with the 8:1's and stock motor, I think it should be going a little faster than 34mph.

11-15-2014, 04:17 PM	#5
JohnnieB Techno-Nerd Join Date: Jun 2011 Location: West Virginia Posts: 19,654	Re: PDS not fast Also, check which field map is loaded in the DCX controller, it has to match the motor (whatever it is), but I don't think that is what is holding it back.

11-15-2014, 05:11 PM	#6
kojo Gone Wild Join Date: Oct 2013 Location: Aynor, South Carolina Posts: 552	Re: PDS not fast JohnnieB, it has 23" tires and I'm pretty sure it's a sepex motor. Can you put a series motor in a PDAS cart and run it w/o changing anything else? And, would that cause it to run so slow? The owner didn't give my buddy another field map to put in it so, it has the #4 map in it now. My buddy went in the program last night and checked some stuff in it and changed a couple of things.

11-15-2014, 05:22 PM	#7
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: PDS not fast Once you add gears (or larger tires) on a stock motor it has much less of a change of obtaining max rpm so the actual speed will be less then the theoretical speed. This doesn't explain why the poster is only seeing 12 mph though with a Alltrax DCX. That controller should make 24+ mph easily at 48v on stock motor as Scotty mentioned. Add 8:1 gears and it will go a bit faster but will never obtain it's stock tire rpm and calculated speed due to the low power output.

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11-15-2014, 05:30 PM	#8
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: PDS not fast I didn't see the post with tire size till now. 23" tires AND 8:1 gears is crazy (IMO). A stock PDS with 18" tires does 5700 rpm at 24 mph with 12:1 gears. Calculated mph of a 23" tire and 8:1 gears is 49 mph at the same 5700 rpm, which you will never reach because the stock motor is too weak. When you put 8:1 gears AND 23" tires it is the same thing as putting 34-35" tires on a stock 12:1 geared cart. Performance will suffer greatly. I doubt the cart can climb a curb from a dead stop.

11-15-2014, 05:45 PM	#9
kojo Gone Wild Join Date: Oct 2013 Location: Aynor, South Carolina Posts: 552	Re: PDS not fast Remember that he doesn't even have the stock motor anymore, it went out with him. He's got some motor that's red from somewhere. Supposed to be a torque motor that he has now. Which definitely doesn't explain why it's only going around 12mph. At least that's what it feels like to me.

11-15-2014, 06:23 PM	#10
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: PDS not fast I've never heard of a sepex motor that is wound so low as it would only do 12 mph on 35" tires (equivalent of 23's and 8:1 gears). No matter what motor you have, it's only turning 1400 rpm at 12 mph in that cart. That is unrealistic. Something else is missing.

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