Manta motor controller issues

[Functional Artist]

I am working on a Cart (El Dingo) with a Manta motor #5655 permanent magnet motor. (advertised as 10 HP / 8000 watts)

I made a simple (contact) controller based on a diagram in the ad I bought the motor from to control this motor. https://www.youtube.com/watch?v=c7q2Lq0P604

It bench tested great but, on the cart, under load, is a different story.

It works like a 3 speed stick shift transmission without a clutch. When driving the cart take off is abrupt and acceleration is good but, as accelerating going from 12 volts to 24 volts and then 36 volts is like driving an old hot rod with a racing shift kit, BANG 1st gear, BANG 2nd gear and BANG 3rd gear.

My main concern is when you decelerate it BANGS down reducing the motor speed abruptly. It seems to be very hard on the motor and cart and especially the chain (stretched on first test drive).

I would appreciate any thoughts or comments on controlling a "big" permanent magnet motor.

 

[itsid]

a "PROPER" motor controller..

sorry, but that's the only thing reasonable IMHO.

MOSFets and such... kellycontroller.com provide a good amount of different types, at reasonable prices (cheap some.. decent at worst)

controlling the motor speed by changing the voltage.. well... for an RC car that might be a good thing (brushless motors) on an EV that's not the best idea ever to put it nicely.

Anyways: buy a proper motor controller and you'll be much easier on your motor and your batteries.

'sid

 

[Functional Artist]

I am kinda new to this.
I have built other carts using electric motors with speed controllers.

They were smaller carts & I usually had complete packages to work with. (off scooters & such)

These bigger motors are a whole new & "exciting" world for me.

This "voltage" controller concept was not my bright idea.

I was simply attempting to accomplish what the the ad recommended. "Let your battery voltage be your speed controller".

With the knowledge I had at the time it seemed like a plausible concept but, I had reservations that's why I ran tests.

I am learning as I go.

Sometimes you learn more from "what NOT to do".

Hopefully these "simple speed controller" experiments, data & results will help to educate others. Thanks

 

[itsid]

Sorry Pal.. we (here in the forum.. not you and me )
had this conversation before a couple of years back..

there are these motors (usually build by a backyard workshop with all the knowledge of the 1960s but NO knowledge of the 1970s)
which are controlled by voltage to control the speed..
and which seem to only exist on ebay.. no selfrespecting company (other than their own 'professional website') even lists their motors.. for a good reason I'd say...
since what they miss to tell you is that it's probably the worst way of doing this really.
And that NO motor is a good generator,
and NO generator is a good motor.
(they clearly claim it's both)
Efficiency and more important usability will suffer on both occasions (voltage controlling and using it as a generator).

I don't say they're dumb ignorant retards... but some people might put it that way
I mean labeling something with "HyperSpeed" alone tells a lot, doesn't it?
Also the term is CONTACTORS since they make contact.. they do NOT sign contracts...

anyways.. as you can tell.. I don't trust them at all... I would recommend them at all.. I wouldn't even mention them to somebody I hate.
But you have one of those.. so you're basically stuck with it for now.

The good thing is.. the motor is likely forgiving (at least I hope they're making the motors as robust as they were in the sixties as well!)
just power it with a constant 48V and you should be fine.

if you want half the speed.. well let the controller shut the motor down for half the time.. COMPLETELY (and no you won't feel that )

take a decent controller.. something that's able to provide all the amperage you need at a constant rate;
(keep in mind that the max rating is likely in the name of the controller.. which is about three times it's constant rating, so keep your eyes open)

'sid

 

[Functional Artist]

Thanks! I really appreciate your advise.

Doin' more research on controllers.

After buying the motor I was trying to be cost consience & creative.
I like makin' stuff. I am not an "off the shelf kinda guy", as I said I was kinda sceptical but, it seemed like a plausable concept & I could not find any info on it not working.

Please send a link to those previous conversations. I am eager to learn more.

Oddly enough, When I went on the ad yesterday to get a picture of the diagram I noticed they now have a link to a small (100 amp) actual speed controller.

It seems very under powered for this type of motor. What are your thoughts?

http://www.ebay.com/itm/Speed-Contr...052492?hash=item5b2888698c:g:QHQAAOSwTZ1XoASi

 

[itsid]

NO just NO.. that's NOT EVEN A SPEED CONTROLLER!!!

It's a likely regulated Powersupply (24 to 48 volts lab PSU)

stay as far away from that company and ANY of their ideas/advice as possible.

That discussion was IIRC scattered amongst several threads...
would take ages to dig everything up, sorry.
but this thread contains at least some basics...

I understand that you think you can at least kind of trust that company in some ways....
and that you're willing to follow their bullsh1t advice.

But really, I cannot even watch you doing that to be honest.
Everything about their products make me want to rage;
mainly because IMHO in close to fraudulent what they do.

For the sake of my own sanity I will NOT help you following anything they said will work.
maybe someone else is willing to take that adventure; I'm not I'm afraid.

Sorry, I really am.

Personally I'd even put that motor on CL and hope someone's dumb enough to get it off my hands just to get rid of that bitter taste.

I understand that you're afraid to loose some money and that you'd like to stick to what you already have and give it a chance.
THEN it'll be a kellycontroller fixed voltage (48V) that you can try and hope for the best.
tell me the amperage rating of the motor (peak and constant) and I'll even go and search a matching controller if you want me to;
(kelly because they're reasonably cheap and still reliable; Curtis or AXE etc. will do too)

but other than that -especially if it contains "Manta" in any part of the description- I'm out.

'sid

 

[Functional Artist]

I didn't mean to get you shook!
I really appreciate your help.
I will never mention or do business with that company again.
I promise!

The motor specs are:
7.90" diameter / 7.75" length
3/4" shaft with 3/16" keyway by 1 1/8" long (threaded center)
Torque constant: 1.14 in-lb/Amp (0.13 Nm Per-Amp)
72 RPM per volt input (3456rpm @ 48V / continuous duty)
A put-up and forget design! Expect decades of dependable service life.
Rain, ice and weather proof electronics.
Heavy duty, long lasting graphite brushes (no controller needed)
10 horsepower continuous duty at 48 volts.
Works for both CW or CCW rotations. (over heat senor not functional on these models)
Epoxy/Lam rotor efficiency = 94% (Brushed motors convert more electricity into usable horsepower)
Weighs ONLY 35 lbs. !! / Dimensions - 8"X 11"X 11"
Can be used as a generator, makes power when turned (Requires 100 amp blocking diode)

I am looking at an Alltrax AXE 7234.
From the research I have done, it looks like it will work & leave room to go to a bigger battery pack later.

Do you thank that is a good match?

What is fixed voltage?
What does IMHO mean?

Thanks, Kevin

 

[itsid]

hehe

I didn't mean to sound rude or anything.. I just don't know how to fix all the mess they provoke with their crap.

you copied the specs from their website haven't you?

94% effiency is.. well.. uhm.. I say it: A LIE!
rpm/volt is a value that's not unreasonable but as important as color to determine the correct controller.

What you MUST know is the internal resistance of that thing.
So, go ahead ; since you have the motor already.. just measure it with a multimeter..
I assume you'll see something along 0.2-0.3 Ohm or so
(roughly 165Amp constant draw) but you'll need to know to find the controller that's right for you
the AXE 7234 might not be ideal (constant rating 125A) maybe the 4845 (const 175A) is a better choice

I don't know, but since every info on their website is at best "beautified" and at worst a plain lie...
I wouldn't even go there to check

So measure the internal resistance and go with that.
(cold and if possible after the motor ran for 5min under no load but at full speed)
BUT CAREFULL! since they disabled the temp fuse for some reason make sure the motor doesn't overheat from that... heat kills permanent magnets really quick;
if it's getting too hot to touch kill the powersupply and measure; no matter if only 1minute passed !!

the lower resistance value is the one you want (oh turn it slowly over by hand while measuring sometimes the commutator is not in perfect contact and turning will find you the best spot [least resistance])

divide 48 by that number and you'll get the max amperage

My const 165Amp guess was solely mathematical.. based on their claims...
10hp are 7457 Watts mechanical.
divided by 0.94 (efficiency rating)
7933 Watts electrical
divided by 48Volts... and you get ~165Amp.

So yeah if that's off... you know whom to blame
(not my math teacher )

Oh yeah.. you'll get the MAX rating not the constant rating
but you can choose the controller by that number if you overestimate by about 15% security margin.
(say max amp is 320Amps calculated.. pick a 370Amp max rated controller or bigger.)

'sid

 

[Functional Artist]

* run the motor for 5 min under no load but at full speed?

To be clear I am going to:

1. remove chain (no load)
2. run motor for 5 min at full speed
(would that be using current set up @ 12v, 24v, or 36v? or just 12v straight off of a battery?)
3. monitor motor temp
4. stop motor then check internal resistance with a multimeter
5. turn by hand to until I find the least resistance

Thanks, I will run a test @ 36v & get back to you.

FYI:

I E-mailed the company that I bought the motor from. wind_turbine_generator
______________________________________________________________________________
Hello,

I purchased a Manta motor #5655 from you ad a few months ago.

($379.95 motor + $54.15 shipping + $56.95 motor mount + $19.27 shipping)

I was thinking of converting a small go cart from gas to electric for my kids.

The main selling point was: "no expensive motor controller required" which your ad states in 4 different places.

I fabricated a "battery speed controller" as your ad recommends.

I was very disappointed!

On the 1st test run, the motor was jumping & jerking around so much that I thought somebody's going to get hurt. It felt like the motor was being "ripped off".

Upon examination I found that, within a 10 min run, the chain stretched (a lot) & the brand new motor mount I bought from you was also bent .

After consulting experts, & from this personal experience, I have found that controlling this motor by changing the voltage is NOT a good concept.

I am NOT happy.

I wasted a few months of my life being misled by your ad.

I wanted to come to you first.

Kevin
______________________________________________________________________________

 

[itsid]

36V would be nice.. but in order to be fair (since excessive runs under no load are still a pain for motors) 24V should do just nicely.

Again: please do not overheat it.. monitor the run and stop as soon as you think something's not right.
(temp, whining sound from a bearing [I hope it's not bushings], visible sparks from the commutator, the distinct ozone smell of electric sparks etc..)

You paid a good amount of money for that motor, and we only want to get it slightly above common operating temperature, not kill it

The rest: that's ecxactly what I meant..

'sid

PS thanks for letting us know about the letter...
I'd be curious what they respond to that... but I'm afraid I assume I already know
(telling you about YOUR faults and a "we tested and it works fine..." comment and at best excuses about the motor mount..)

 

[Functional Artist]

I ran the motor & tested the internal resistance.

The meter reads 1.5 even after turning by hand. while turning the numbers fluctuate but, always come back to 1.5.

Does that sound right?

48 divided by 1.5 = 32

 

[itsid]

not really...

was that a digital test?
did you check the setting for decimals?

Where did you measured? (motor taps or cable ends) and was the battery still attached?

if you measured across the motor taps without batteries attached I'd be baffled
if you haven't corrected the readout for your current decimal setting to say the least.

Again I'd expect something around 0.2 Ohms.. 0.15 would be nice in fact.. 1.5 Ohm is BAAAAD
(that means your motor maxes out at ~864 Watts wich is a tenth of the advertised power and not really enough for the performance you had during the test drive video )

So yeah... no

Oh I might have said 48 above... but that 48 is your motor volts (IIRC in your case 36V instead)
Sorry..
so it's 36V you need to divide (i.e. 24Amps max..... 240 Amps again much more likely)

And since I messed up above (I can't even tell where the 48V came from to be honest...)
I'm afraid that motor controller you picked (Alltrax AXE 7234) is surely not going to cut it for you I'm afraid.

Please check again, maybe test a different meter if you have.

'sid

 

[Functional Artist]

Maybe I did something wrong
http://www.diygokarts.com/vb/images/smilies/censored.gif

Please bear with me.

I am not an pro at this, as I said, I am learning as I go.

I will test again & again if I have to.

I want to learn how to do this stuff.

I have a cheap HF multimeter.

to be sure:

In the Ohms section on the meter which setting should the dial be at?

200, 2000, 20k, 200k or 2000k?

How do check the setting for decimals?

When the data from the test was not consistant or even close to what you suggested, I ran the test again & again in every setting & still odd numbers.

What am I doing wrong?

 

[itsid]

I was hoping for 20 or even two to be honest
200... and it should show ONE decimal place ( ie maxes out at 200.0)
unfortunately that's not low enough since you'd need two, better three decimal places
to get a good reading

I think I have one of those too somewhere...

It's 6am so I'm a bit reluctant to search for it to see if we can 'cheat' our way through this;
else I'm afraid I'd ned to ask you to borrow one from a neighbor or friend that has a more accurate one.

there's a magnificent one on aliexpress (made by fluke! ) for IIRC 40 bucks...
but that wouldn't help us either here I'm afraid I doubt any digital multimeter will actually...

I'll let you know as soon as I got some sleep and an idea how to rig it up .

'sid

[EDIT]
Mahlzeit..
Soo, a voltage divider is all I can come up with I'm afraid.. checked the internetz and they say it'll work nicely.

So I think we can stick with that
It's easy to make, a tiny bit tedious tto measure though.

Anyways: You need to find me two things:
A wallwart powersupply with anything from 3 to 9 volts but at least one amp of max current delivery.
but more importantly : A resistor (ceramic would be great, film will do) (you know one of those little guys in the striped shirts )
anything that's nicely readable with your multimeter and not too big (below 1kOhm)

If you can't find the powersupply, no worries.. if you can't find a resistor: buy one (220 Ohm is quite common and of nice size for us.. since you buy one anyways ... buy a 2 or 3Watt version)

let me know when you have (and what size you read exactly [measured with your multimeter!] not from the box )

'sid

 

[Functional Artist]

Sorry, I haven't got back sooner.

I still can not find anyone with a "good" multimeter.

I have been to battery shops, starter & alternator repair shops & even electronic repair shops still no luck.

I went to check out the one you mentioned but, the web site is not in English.?

I have also been looking for the 2 or 3 watt resistors you mentioned but, the largest I can find locally is 1 watt.

Will a 1 watt 10 Ohm resistor work for the test?

They came 2 in a package. Can they be doubled up to make a 2 watt 20 Ohm resistor?


* Here is the answer, to the letter I sent to the place where I bought the motor from:

One trick is to run the first stage to a 6 volt battery and not a 12 volt.
Also your vehicle may just be too heavy for this type of unit. In a small Kart the wheels spin a bit
and that usually makes people happy and feels "RACY"
For low start speed try using 2 X 6 volt battery's as that works very
well in a heavyer kart.
Next time you have problems contact me right away.
Ed

* I responded:

Sir,

I am NOT going to debate this with you.

Your ad is fraudulent & misleading.

You are setting people (your customers) up for failure.

Your ad recommends using this motor for a go cart.

Then your ad clearly states (4) times "NO EXPENSIVE CONTROLLER REQUIRED"

But, in reality, using that motor on a go cart without a speed controller is destructive & dangerous.

Using the "voltage" controller as you recommend is even worse.

To take a mechanical devise & abruptly go from standstill to 864 RPM's (or even 432 as you now suggest) & then immediately to 1,728 RPM's & then immediately to 2,592 RPM's is a recipe for disaster.

It "will", not maybe it "will" damage the chain, sprockets, motor mount, motor & battery's.

I wasted half of my summer, based on claims in your ad.

* They responded:

You would be the first person out of thousands that was not happy.
Send me a photo of your system and I will look for wiring errors.
Ed

* I responded:

There are NO wiring errors, the whole concept (operating a motor like this without a controller) is dangerous & destructive.

This fraudulent & misleading ad should be removed!

 

[itsid]

Well, a MUCH nicer and better response than I was expecting to be honest.

Still unfortuinately far from a solution

(there is indeed a solution to that, but that'd require not 6V steps but ideally a gradual increase of the voltage .. which is possible with - this is where it gets nasty - a special controller )

aaanyways, I'd say leave it be, I totally understand that you're upset ..
but barking up the tree doesn't help you fixing it I'm afraid.

So, back to the measurements.. 10 Ohms are a tiny bit on the low side I'm afraid;
1Watt is perfectly fine though.

Anyways, let's TEST with the 10 Ohm resistor, if you already have it; and then we'll see what kind of result we achieve

Now; first things first:
Do you have a powersupply as I mentioned above?
If you don't, take a 9V battery.

Take it, and connect a wire to the one of the poles (positive or negative doesn't matter at all)
the wire should be long enough to reach one of the motor taps.
have that?
pro tipp: use the shortest thickest wire you can.

Do the same for the other pole on the power supply.
(Do not connect the two ends to each other or the motor just yet.. you'll likely fry the powersupply)

Now, to ONE of the two wire ends connect the resistor you got,
get your multimeter ready (set it to volts)

and connect it to the motor;
now measure the voltage across the resistor (AND ONLY the resistor!!) get as close to the bead as possible and write down the voltage reading
toggle the DMM to read resistance and measure the de fecto resistance for it as well
write that down as well.

now, set the DMM to volts (millivots likely) and read the voltage across the motor taps.
write that down as well.

and just to have a comparision value: read the voltage across the battery/PSU poles as well
always as close to the unit you're interested in as possible

You should now have four values written down, three voltages and one resistance.. hopefully labelled nicely

first just as a control, add the voltages from the resistor and the motor and see how far off you are from the PSU/battery voltage readout.
I hope your readings are really close, since if you're not, you'll need a stronger powersupply/battery

Worst case: repeat the process with one of your 12V batteries... but be careful not to zapp yourself.
also make sure to remove the chain first and clear all rotating parts of course


Okay, let's assume you're close enough to feel confident with the rest.

NOW: bring the two smaller voltages to the same power of ten
(i.e. multiply the voltage by 1000 to get millivolts)

divide the read Ohm value by the voltage you measured across the resistor.

multiply that number by the voltage you read across the motor taps and you'll end up with it's resistance.

Now, that was confusing, wasn't it?

Okay again in an example:
#############
(all numbers are made up and don't reflect real world measurements )

So assume you got a 9V powersupply and a 10Ohm resistor.

(conX) in the following are the connections you'll need test with your DMM

BATTERY (con1) RESISTOR (con2) MOTORTAP1 -> MOTORTAP2 (con3) BATTERY


You measured
9 V across con1 and con3 (as close to the PSU as possible...)
8.7 V across con1 and con2 (as close to the resistor as possible) [8700 mV]
9.7 Ohm across con1 and con2

and finally
300 mV across con2 and con3 (directly across the motortaps)

the precheck tells us our result will be nice (8.7V + 300mV = 9V... )

9.7 / 8700 = ~0.001115

0,001115 * 300 = ~0.3348

So the resiustance of the motor would be 0.3348 Ohms in this example.
#############


'sid

 

[Functional Artist]

I tried the test with a 9 volt battery. Numbers did not add up.

So, I ran the test with a 12 volt battery.

Note:
1. the shaft rotated normally connected directly to 12 volt battery but, did not even attempt to turn with the resistor attached.

2. the resistor got really hot during the test.

Here is the data I recorded:

13V PSU across con 1 & con 3
12.9V (12900mV) resistor across con 1 & con 3
10.6 Ohm resistor across con 1 & con 2

.10V (100mV) motor across con 2 & con 3

precheck 12.9 V + 100mV = 13 V

10.6 Ohm / 12900 mV = ~ .0008217

.0008217 x 100 mV = ~.08217 Ohms

Does this seem right???

*(about to drop kick this thing off the back porch)

BTW: Yesterday, a representative from Motenergy (I believe the parent company that makes these motors) finally returned my call from a few weeks ago, when I was trying to find "good" specs on this motor for you.

He said that a Manta 5655 was about the same as a Motenergy ME0709.

The main difference was that the case on one is a little longer.(5655 @ 174.5 vs. ME0709 @ 175.5)
Here is a link

http://ep.yimg.com/ty/cdn/yhst129399866319704/ME0709drawing.pdf

if that is helpful.

 

[itsid]

0.08217 Ohms.. that's nice seems to alright...

let's see what it turns out to be powerwise (okay.. max short burst power...)
36V / 0.08217 Ohm = ~438 Amps

That's the absolute max the motor is able to draw (it'll quickly reduce as soon as the coils heat up) but.. that's also a number I assume the motor is not able to withstand for any extended period tbh... (and it won't need to due to the coils heating up)

I think rougly 80%-90% of that should be safe to assume short bursts...and half of that for continuous use with proper cooling.

So 350-400 Amps peak current and 175-200 Amps continuous
which turns out to be (36*175) 6.3kW to (36*200) 7.2 kW continuous or 8.45 to 9.66 horses

Yepp, that seems very plausible to me
I can't tell if that's indeed your real world value or not...
But it seems to be at least really close to it!

So I'd say get a controller capable of 200Amps continuos powersupply..
I'd dial in towards 250Amps tbh (maybe 300 if that's the next step)

Keep in mind that you couldn't "overrate" the controller really.. the larger it is the cooler it runs under the load of your motor;
on the other hand too small controller can (if cheap and unprotected) overheat and fry with a motor too thirsty for it's capabilities.

for all I know the motenergy ME0709 is max 300Amps and 125 cont. or something.

And if THEY indeed made your windings and brushes you're perfectly fine keeping that motor.
You might want to ask them about reinstalling (providing the sensor) the temp_fuse in order for you to regain a bit of additional security.. especially PMDC motors can roast pretty quick considering permanent magnets can cook off their magneticity (making up words as I go since 1976)

Ask them for advice, If I had to make a guess a 220°C fuse should do to keep the magnets intact.. the resin on the coils might need a much lower value though *shrugs*
(to dial in on the safe side.. I'd lean towards a 120°C fuse to protect both)
Or maybe just a thermistor and a microprocessor to read and control the temp on it's own..

Anyways...

kelly suggest the kdz7240124v for the Mars ME0709 (which is the motenergy ME0709 ) (300 bucks)
http://kellycontroller.com/kdz7240124v-72v400apm-with-regen-p-964.html

personally I'd get the next bigger version of it: (320 bucks)
http://kellycontroller.com/kdz7255024v-72v550aseriespm-p-965.html
it's 20 bucks more alright.. but in case your motor draws more power, you have the controller to provide that without frying.
(yes it has a 100°C fuse installed that shuts down if the controller gets too hot... still... 20 bucks ...on an already expensive controller.)

Anyways, a similar sized Axe (4855) is around 600 dollars and a curtis isn't even available in that size for all I know.

Ah well... I'm sorry I don't have better news for you

But at least now you know.

'sid

 

[Functional Artist]

Yes, now we know.

That's great news. Were finally making progress.

I agree, it's best to go with the bigger version of controller.

I would like to get everything I need ordered.

What else is needed to make this work?

I know we need a throttle.
(to tell the controller what we want it to do)

Will the simplified 0-5v throttle pedal Kelly offers be adequate for this situation?

Also, in other set ups, I have seen, they use:

a 3 amp diode
a precharge resistor (220 Ohm/36v or 470 Ohm/48v)
a 250 amp fuse

Are those things necessary with this controller, motor, battery set up?

Oh yea, Thanks again, for your patience & fantastic advise.

 

[itsid]

The throttle will work (apart from it being ugly it's alright.. not waterproof though)
any 0-5V throttle will you can even hack and glue a pedal to a scooter thumbthrottle and it'd do..
Heck, I think even a 0-5 kOhm poti will work if I'm not mistakin'...

Just pick the one you like or which is cheapest to get.


A beefy diode and precharge resistors are usually to protect the contactor (utterly beefy solenoid) but the precharge resistor should be in the realms of 1kOhm for all I know (some beefy wattage too ..IDK 10?)

Anyways a contactor is a good idea, otherwise you'll have a live motor wire no matter if the controller is on or not and under the worst of circumstances you can spotweld your switches.

I've seen setups without but I cannot tell you if they failed or not.. *shrugs*

The fuse is always a good idea... 250 amps is a little on the low side though;
considering the motor can draw 300 at least on full throttle. it'll certainly blow in short order.
A 500 amp fuse is much closer to what you'd need I'd say.

A control box (and by that I mean physical switches and such) is also a good idea..
an on/off switch for sure, a brake switch (for the brake pedal) to enable regen braking and disable forward momentum from the motor (otherwise your brakes will have nearly no effect at all)
(IIRC the KDZ can motor brake with a 0-5 pedal on the brake as well.. don't quote me on that though)
some diodes as indicators... and maybe panic button (aka kill switch).

Search for the KDZ manuals on their site and see what's in there.. read the manual now..
(I think they have some basic wiring diagrams as well... they should at least)

I might have forgotten something, maybe even something important;
so better check the documentation to see what they ask for.

And you're very welcome!
but if you would like to do me a favour.. give that thanks button a hug

'sid