R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 05-27-2013, 07:31 PM   #1
Tech Master
 
Join Date: Nov 2012
Posts: 1,122
Trader Rating: 13 (100%+)
Default Rotor shimming

When shimming a rotor ( 17.5 revtech ) I know it's best to get the rotor closest to the sensor without touching. When its at that point do I add shims on top to get rid of end play? Or just put the spacer and whatever it is, it is?
JOE SI is offline   Reply With Quote
Old 05-27-2013, 08:06 PM   #2
Tech Elite
 
Josh-n-ya's Avatar
 
Join Date: May 2011
Location: Alameda, CA
Posts: 2,190
Trader Rating: 75 (100%+)
Default

I sometimes add shims and that depends on the play. Ive also took a shim and wet sanded it down and put on pinion side.
Josh-n-ya is offline   Reply With Quote
Old 05-28-2013, 07:03 PM   #3
Tech Master
 
big al's Avatar
 
Join Date: Jan 2002
Location: Olympia,Wa
Posts: 1,026
Trader Rating: 10 (100%+)
Default

why is it best to keep it close to the sensor? I assumed you would want the rotor shimmed so that it would spin in the space with the strongest magnetic field..
big al is offline   Reply With Quote
Old 05-28-2013, 07:15 PM   #4
Tech Master
 
Join Date: Nov 2012
Posts: 1,122
Trader Rating: 13 (100%+)
Default

Quote:
Originally Posted by big al View Post
why is it best to keep it close to the sensor? I assumed you would want the rotor shimmed so that it would spin in the space with the strongest magnetic field..
Not really sure but that's what a few have told me and they've been around a lot longer than me and some built their own motors from scratch
JOE SI is offline   Reply With Quote
Old 05-28-2013, 07:34 PM   #5
Tech Master
 
Mr RCTech's Avatar
 
Join Date: Dec 2005
Posts: 1,291
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by big al View Post
why is it best to keep it close to the sensor? I assumed you would want the rotor shimmed so that it would spin in the space with the strongest magnetic field..
This is true.


Some Racers move the rotor closer to sensor when using a high torque rotor to adjust the power band.
Higher Rpms at the cost of some torque.

Its a tuning thing...
Mr RCTech is offline   Reply With Quote
Old 05-28-2013, 08:29 PM   #6
Tech Regular
 
hotrod1933's Avatar
 
Join Date: Feb 2012
Location: The Shire, Sydney Australia
Posts: 312
Trader Rating: 8 (100%+)
Default shimming

so does end float cause variance in rpm. some motors out of the box have like .030" float. should you always shim down to say 2 thou just a little to allow for rotor to grow with heat although can should grow quicker as it is alum.

another way to put question how does sensor count, off the rotor i assume. if so the better the gap error the more even the count

i normally just buy and run em.
__________________
XRAY T4-15 -- nbhc.com -- powerhouse performance -- sma.org
hotrod1933 is offline   Reply With Quote
Old 05-28-2013, 10:31 PM   #7
Tech Elite
 
ta04evah's Avatar
 
Join Date: Oct 2010
Location: Sydney, Australia
Posts: 2,614
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by hotrod1933 View Post
i normally just buy and run em.
So do I until I take them apart for cleaning and then forget which shims go where...

I too was told to shim the rotor so that it sits within the magnetic field ,and allow a little free play for heat expanding etc.

Cheers
Rob.
__________________
Castle Hill RC On Road Facebook https://www.facebook.com/groups/121817254587521/
FatBear RC Videos https://www.youtube.com/channel/UCjiAhwa-rk5Vas2rv5IBD4A
ta04evah is offline   Reply With Quote
Old 05-29-2013, 07:27 AM   #8
Tech Master
 
WIITA's Avatar
 
Join Date: Jun 2008
Posts: 1,590
Trader Rating: 42 (100%+)
Default

Quote:
Originally Posted by ta04evah View Post
So do I until I take them apart for cleaning and then forget which shims go where...

I too was told to shim the rotor so that it sits within the magnetic field ,and allow a little free play for heat expanding etc.

Cheers
Rob.
I generally believe that the motor works the best when the rotor is centered in the magnetic field.
Here's my suggestion:
Place two .20 shims and one .10 shim on the sensor side of the rotor
Place one barrel shim on the pinion side of the rotor and assemble.
Spin the rotor and let the rotor center in the stator. Push the rotor twards the sensor. Spin the rotor again let center, then pull the rotor twards the pinion side. I usually shoot for a tiny bit of slop in both directions.
__________________
Team CRC / Sanwa / Team scream / Genesis RC / Hobbywing / TQ Wire / Schelle / MIP / RC^2 / TEKNO / BoomRC

Last edited by WIITA; 05-29-2013 at 06:13 PM.
WIITA is offline   Reply With Quote
Old 05-29-2013, 09:59 AM   #9
AMZ
Tech Regular
 
AMZ's Avatar
 
Join Date: Jan 2009
Posts: 380
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by WIITA View Post
I generally believe that the motor works the best when the rotor is centered in the magnetic field.
Here's my suggestion:
Place two .20 shims and one .10 shim on the sensor side of the rotor
Place one barrel shim on the pinion side of the rotor and assemble.
Spin the rotor and let the rotor center in the stator. Push the rotor twards the sensor. Spin the rotor again let center then pull the rotor twards the pinion side. I usually shoot for a tiny slop in both directions.
I think the above ,is your answer.
AMZ is offline   Reply With Quote
Old 05-29-2013, 08:04 PM   #10
Tech Elite
 
ta04evah's Avatar
 
Join Date: Oct 2010
Location: Sydney, Australia
Posts: 2,614
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by WIITA View Post
I generally believe that the motor works the best when the rotor is centered in the magnetic field.
Here's my suggestion:
Place two .20 shims and one .10 shim on the sensor side of the rotor
Place one barrel shim on the pinion side of the rotor and assemble.
Spin the rotor and let the rotor center in the stator. Push the rotor twards the sensor. Spin the rotor again let center, then pull the rotor twards the pinion side. I usually shoot for a tiny bit of slop in both directions.
Thanks, I tried that and got the rotor to be in the center of the magnetic field without rubbing against the sensor board.
Will see if it does anything to the performance of the motor on the weekend.

Cheers
Rob.
__________________
Castle Hill RC On Road Facebook https://www.facebook.com/groups/121817254587521/
FatBear RC Videos https://www.youtube.com/channel/UCjiAhwa-rk5Vas2rv5IBD4A
ta04evah is offline   Reply With Quote
Old 05-29-2013, 08:28 PM   #11
Tech Adept
 
tdu verney's Avatar
 
Join Date: Mar 2005
Location: Del City Speed Shop
Posts: 226
Default shimming the rotor

Quote:
Originally Posted by WIITA View Post
I generally believe that the motor works the best when the rotor is centered in the magnetic field.
Here's my suggestion:
Place two .20 shims and one .10 shim on the sensor side of the rotor
Place one barrel shim on the pinion side of the rotor and assemble.
Spin the rotor and let the rotor center in the stator. Push the rotor twards the sensor. Spin the rotor again let center, then pull the rotor twards the pinion side. I usually shoot for a tiny bit of slop in both directions.


yep center the arm... It's how we did it back in the days of brushed motors, one of a few tricks to tunning a quicker motor...
tdu verney is offline   Reply With Quote
Old 05-29-2013, 09:23 PM   #12
Tech Master
 
Join Date: Jan 2006
Location: Kansas City, MO
Posts: 1,260
Trader Rating: 13 (100%+)
Send a message via AIM to HenBeav
Default

Closer to the sensor board adds timing if you are in a locked end bell situation. If not just shim it where it spins best.
__________________
[URL]http://www.fastlanehobby.com[/URL]

Support your local Lowe's, Walmart and Layne Machine Works INC.
HenBeav is offline   Reply With Quote
Old 05-29-2013, 09:33 PM   #13
Tech Addict
 
Jethroz's Avatar
 
Join Date: Nov 2011
Location: Frederick, MD
Posts: 572
Trader Rating: 51 (100%+)
Default

Quote:
Originally Posted by WIITA View Post
I generally believe that the motor works the best when the rotor is centered in the magnetic field.
Here's my suggestion:
Place two .20 shims and one .10 shim on the sensor side of the rotor
Place one barrel shim on the pinion side of the rotor and assemble.
Spin the rotor and let the rotor center in the stator. Push the rotor twards the sensor. Spin the rotor again let center, then pull the rotor twards the pinion side. I usually shoot for a tiny bit of slop in both directions.
This is pretty much how I baseline all my motors. That small amount of force the rotor is placing on the shims causes friction. Friction = heat and less efficient. I've seen the top end on most 17.5 motors jump 1-2000+ rpm (*unloaded) just from shimming alone.

It's just one more of the small tuning things you can do to get the most out of your motor. I have went through numerous stators and rotors trying to pair up the best float with a rotor stator combo. Things really get expensive when you are looking to pair a matched low resistance stator and a balanced specific rotor which also have a good float.
Jethroz is offline   Reply With Quote
Old 06-01-2013, 04:54 AM   #14
Tech Master
 
idbdoug's Avatar
 
Join Date: Oct 2006
Location: Above FltLevel300
Posts: 1,561
Trader Rating: 33 (100%+)
Default

I know my fantom tuned motors usually have 2 shims which equal about 1mm on sensor board side. Any extra shims are placed on same side as barrell/pinion side of motor
If you r running a RevTech, be careful with going less than 1mm of shims on sensor board especially if u r running a 12.5HT. I fried/scrambled two sensor boards before realizing what was going on, not sure if same problem will occur with D3.5 or Killshot. Problem occurred because I was testing allot of different rotor combos in my Revtech but I would think u would still have the same issue on newer motors
idbdoug
idbdoug is offline   Reply With Quote
Old 08-01-2013, 12:02 AM   #15
Tech Elite
 
Josh-n-ya's Avatar
 
Join Date: May 2011
Location: Alameda, CA
Posts: 2,190
Trader Rating: 75 (100%+)
Default

The Higher the KV value the higher the RPM is what I have been seeing on a motor tester! When you adjust timing + those numbers increase. What is a good range for KV and RPM to be at to have a fast but torqy motor? How would you test for torque? Would using a High Torque rotor be the only way to increase torque? Also have been testing some rotors. Are the best rotors pretty evenly matched as far as + and - or do you want + value to be higher or lower? What are some good 12.3 rotor + and - numbers in HT, Broadband, RPM and the same question for 12.5 rotors.
Josh-n-ya is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 12:19 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net