Where to get a drive sprocket to fit an eTek/Mars

[silverrich1]

you'll burn his motor giving him advice about pancake motors. no pancake motors do not survive over-volting well, perm pmg132 are the worst for high voltage melt-down, the old original etek pictured is terrible at over-volting, max 60v and that's pushing it. ideally he wants a D series lynch motor, D132 for more than 88v etc... it'll do it.
72T sprocket / #40 chain / #40 7/8" 3/16 14T for the original etek = 0-70mph with great torque.

Best thing to do is to stick to 60volts. period.

Yes, it's a 48V motor, but it is a range, 48-72V. Take a look at EVAlbum, most of the etek users on motorcycles use 72V. Same thing with Agni, although, they can go to 96V+

on a brushed motor, going 1.5-2x the base voltage is nothing big. Especially at low voltage like 72V.

[frodus]

That's a MAYBE.... Overvolting this motor to 72V isn't what really hurts it, The issue is people overamp this motor at the higher voltage and overpower it. They put too many amps into it and it gives them issues.

There are tons of people using 72V on the mars and Etek motor on evalbum without any issues.
http://evalbum.com/mtrbr/MARS

Hell, Mars 0709 is a 72V motor on their datasheet for it. I've seen curves for other Mars motors and it's the same thing, they have 72V curves. It's not about the overvolting, it's overloading the motor and not putting in place correct current limits on the motor controller.

I've not seen any examples of a 48V pancake motor "melting down" at 72V with correct current limits in place..... maybe you would be kind enough to provide some examples? I'm being serious, if there are example I think the myself and the OP would like to know. Maybe there's some quality issues with new ones?

[Jozzer]

The problem with overvolting these motors is the max RPM that they fall apart at. As I understand it, the Etek can do this at 4krpm or less (especially if it's been heated till the solder softens!), which would be not much over 48v...


Jozz

[frodus]

If that is the case, and they fall apart at higher RPM's, then I guess someone should say something to Motenergy and Perm so they can change their datasheets and inform their vendors they they won't run at 72V. Maybe the original B&S was 48, but Mars was in the subject line and it sounds like he hasn't chosen a motor yet.

72V curves:
0709 curve at 72V From Mars/Motenergy:
http://www.evdrives.com/images/Motors/M ... _72vdc.pdf

PMG132 72V curve on PMG's website:
http://www.perm-motor.de/en/download/do ... nical-data

Webpages and datasheets stating 72V
Motenergy:
http://motenergy.com/mebrtoen.html
http://motenergy.com/me1003.html
http://motenergy.com/me0709.html

Perm:
http://www.perm-motor.de/en/products/dc-motors
http://www.perm-motor.de/en/download/do ... nical-data

Distributor websites stating 72V with datasheets and curves:
Motenergy:
http://www.cloudelectric.com/product_p/mo-me1003.htm
http://www.thunderstruck-ev.com/motenergy-me1003.html
http://www.evdrives.com/mars_motor_me1003.html
http://www.electricmotorsport.com/store ... me1003.php
http://www.cloudelectric.com/product_p/mo-me1008.htm
http://www.cloudelectric.com/product_p/mo-me0709.htm
http://www.thunderstruck-ev.com/motenergy-me0709.html
http://www.evdrives.com/mars_motor_me0709_etek-rt.html
http://www.electricmotorsport.com/store ... me0709.php

Perm:
http://www.cloudelectric.com/product_p/mo-pmg-132.htm
http://www.thunderstruck-ev.com/perm-pmg-132.html
http://www.electricmotorsport.com/store ... pmg132.php


So wouldn't you think it'd be a huge liability for Mars and Perm to advertise 72V but when run by individuals at 72V they fly apart/burn up/melt down?

I've seen and riden Perm motors running at 72V on a dirtbike with A123 and an Alltrax without any issues. Several conversions with an Etek 0709 and 1003 at 72V without issues. Those were the ones I was referring to. I should have been more specific.... Mars/Motenergy sells 72V rated pancake motors.

Long and short of it, run the motor at manufacturer recommended specs.

[Njay]

I think there's a slight confusing here, frodus; we're talking about the eTek only when we speak of 48V limit. Mars has other models that it specs to more than 48V. The Mars equivalent of the eTek (eTek => B&S) is the Mars708, which is also spec'ed at 48V max, although spec'ed at 5krpm max. I think I saw the limit of the eTek to be 4krpm, but I don't remember where and it was not in the datasheet. The datasheet shows only tests up to some ~3550rpm, so it makes sense that the limit is 4krpm.
I do agree with you that voltage is not that important given that current/temperature is under the limits, but there's still the max rpm limit to consider.
Furthermore, the eTek is already tough on the controllers due to its low inductance. Raising the voltage also raises the current raise speed. Many details to consider.

[frodus]

Exactly.... Mars/Motenergy markets their 0708 and 0709 as Etek motors..... I had no clue which you're referring to. If you're truly speaking of the original B&S Etek, then yes, 48V is probably about it for that motor. I've not seen a curve for 72V on that (nor at 48V for that matter).

If you need 72V, the Perm and 0709 from Motenergy are rated for 72V operation, and as you mentioned, that's dependant on temperature and current as well. The even better solution is an Agni 95R Reinforced motor, they're made for higher RPM... and overvolting

[Njay]

Exactly.... Mars/Motenergy markets their 0708 and 0709 as Etek motors.....

A common confusion, but actually not true . It is the retailers who name them "Eteks"; Motenergy never used those terms and actually discourages their use as far as I now ("Etek" is a trademark from B&S).

There's only one Etek, the original B&S Etek. The Moternegy are MExxxx. ME0708 has performance equivalent to the Etek (but 42% more weight!). You can find some Etek curves on-line (not generated by B&S but by some other companies, I think), but here's one (with some presentation changes I made for inclusion in an article):



I'm going to squeeze this old Etek, then we'll see. If it blows, the other only motors worth considering are the Agnis yes, or the LEMCOs (roughly same tech), but I'll have to save a ton of $$ for that.


update: changed "eTek" to "Etek"

[frodus]

touche,

it's EMS and a few others that call it etek.