R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 08-04-2004, 09:24 PM   #31
Tech Elite
 
Join Date: Jul 2004
Posts: 2,416
Trader Rating: 7 (100%+)
Default

Timing refers to the alignment of the brushes with respect to the magnets in the motor can. As you advance the timing, you are essentially shifting where the electromagnets created by the armature "push" in relationship to the static magnets of the can. As a result, you increase the top end of the motor, and reduce torque. However, the motor tends to heat up more and become less efficient. I agree with fatdoggy that the better choice for club racing tends to be lower timing and gearing taller. Jedi, note: I said tends to be better . Jedi seems to be the nitpicky type. Advancing the timing of the motor will tend to increase power, since the additional gained rpm exceeds the torque lost. But, if you advance the timing too far then both torque and rpm will be lost, resulting in less power. So, let's say you advance the timing from 12 to 18 degrees. You'll have more rpm but need to gear slightly shorter to make up for the lost torque. All in all, you should theoretically have a faster car in top-end. So, why don't we all run 40-50 degrees of timing, right? After all, we can gear down....

1) Inefficiency. The motor doesn't convert current to mechanical power as effectively, which means more battery power is turning to heat.

2) Motor fade. As the motor heats up, the magnets will further weaken, making the motor even more inefficient and "soft".

3) Torque issues. Even if the motor is cool, advancing the timing beyond a certain point will really start dragging down the low-end of the motor such that you can't compensate with gearing. So, you could have a car that is a rocket, but ends up taking several hundred feet to accelerate

So, 12-18 degrees of timing tends to be a good range. I don't think it is worth spending a lot of time messing around with it. All else equal, you could consider lowering the timing a little if the track is really hot. Otherwise, the factory timing is correct 99 percent of the time.
071crazy is offline   Reply With Quote
Old 08-04-2004, 09:33 PM   #32
Tech Master
 
Join Date: Mar 2004
Location: Earth
Posts: 1,039
Send a message via ICQ to rcnewb2004
Default

So the "timing" really is the angle between the electro magnets and the static can magnets? And it sortof decides "when" the push against the static magnet will be made?
rcnewb2004 is offline   Reply With Quote
Old 08-04-2004, 09:49 PM   #33
Tech Elite
 
Join Date: Jul 2004
Posts: 2,416
Trader Rating: 7 (100%+)
Default

basically, yes.
071crazy is offline   Reply With Quote
Old 08-04-2004, 10:27 PM   #34
Tech Elite
 
fatdoggy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: MD USA
Posts: 3,642
Default

Just something else to think about.

More timing = More off power drag. More deceleration.
Less timing = Less off power drag. Less deceleration.

Last edited by fatdoggy; 08-05-2004 at 12:31 AM.
fatdoggy is offline   Reply With Quote
Old 08-04-2004, 11:19 PM   #35
Tech Elite
 
tandman's Avatar
 
Join Date: Feb 2004
Location: airdrie
Posts: 2,966
Trader Rating: 6 (100%+)
Send a message via Yahoo to tandman
Default Surikarn 10x1

This motor rocks. Geared 8.44(18 degrees timing) on a medium sized not real tight track in an IRS TC3 makes the car fly! Excellent toque out of the corners, great speed on the straights and excellent run time.
Highly recommended.
tandman is offline   Reply With Quote
Old 08-04-2004, 11:25 PM   #36
Tech Regular
 
mwcet8k's Avatar
 
Join Date: Apr 2004
Location: Arizona
Posts: 266
Default

Quote:
Originally posted by rcnewb2004
mw: a diode will do what I have mentioned, however, why does it have to be a schottky diode, i heard it has a "high forward voltage" or something.... what advantage does the "schottky" diode have compared to just a plain old diode?

i bought the motor. i am so eager to see it.
Man, you ask some of the toughest "newbie questions" I've heard in a while. Most newbies ask questions like, "What's the difference between the black wire and the red one?"

I'll admit that I don't know exactly what the answer is to this one, but I'll give it my best educated guess. If anyone knows a better answer feel free to chime in.

A schottky diode is basically a one-way filter for electric current. It allows current to flow in one direction, but not the other. When you apply braking to your esc, it actually causes the motor to slow down rapidly by shorting it. Over time, this short is what caused the brake fets in older speedos to burn out. Because the schottky only allows current to flow in one direction, it "buffers" this short, so to speak. The "high forward voltage" you heard someone mention is probably just their way of saying that the diode only allows current to pass when you apply forward throttle (forward "voltage") to the motor. It won't allow anything else. You can quickly destroy a schottky if you ever install one on a motor connected to a reversable speedo. As soon as you apply reverse throttle, it will be toast.

As far as how a schottky compares to other diodes, I honestly have no idea. Schottky's are the only diodes I've ever used for anything, so I've really got no point of reference to go off of. Anyone know?
mwcet8k is offline   Reply With Quote
Old 08-05-2004, 12:44 AM   #37
Tech Master
 
Join Date: Mar 2004
Location: Earth
Posts: 1,039
Send a message via ICQ to rcnewb2004
Default

mw: cool I think you helped me figure it out now. The specialty of the schottky diode is that it has a low forward voltage. That probably means the voltage required to activate the "oneway" effect of the schottky diode is lower than of a normal diode. However, I could still be wrong because this is still my guess. So ppl out there, please correct me if i am wrong!

and not too long ago, i did ask the question "is there a difference between a red and a black wire"? hahah and well u know what happened to me hahah... i got schooled.

Tanman:
Thanks man... I ordered the motor. I am just getting too much positive feedback on this motor. I think I will gear it to 8.0-8.5 depending on my track and adjust the timing accordingly. Thanks for all the great advice guys!


Fatdoggy:

I am sorry, I am not too sure I understand your "power drag" concept... can u explain it further?

Just think of me as not just a newb, but a retard at the same time.
rcnewb2004 is offline   Reply With Quote
Old 08-05-2004, 02:50 PM   #38
Tech Elite
 
fatdoggy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: MD USA
Posts: 3,642
Default

Quote:
Originally posted by Big Jim
Hi FD,

I'm wondering why anybody posts anything about motors on that site when people have to come here for the answers anyway. If someone does post any worthwhile info there, in 3-4 days you'll never find it again.

I never really thought about it before because you can always dial in or out as much drag brake as you need anyway from the TX on a good radio regardless of how much timing is on the motor.

But makes sense though. As we all know, drag brakes is a function of the TX setting that controls that part of the ESC circuitry but it's really just "partial dynamic braking".
Under a dynamic braking situation, the motor becomes a generator putting out power instead of taking it in. This is where the term "regeneration" comes from. In theory, under braking when the motor is generating power, it sends it back into the batteries, thus adding a bit of runtime.

Electrical timing on our motors in any amount and on either side of the "0" point is a three-way relationship between the brushes, armature coils (and segments) and the magnets. Running a lot of advanced timing on a motor causes it to draw more current under heavy loads. It does this because it takes power to make power. If you want more punch you advance the timing so the motor draws the amps it needs to make the power to push your car harder out of the corner.

With the timing set the same and under a braking situation, the motor puts out a lot of amps the same way as it was using coming out of the last corner. Anytime a generator is putting out a lot of current, there's a bigger load on the drive source. The drive source of this generator in your car during dynamic breaking is the car's momentum. More drag on the car's momentum and you slow down quicker.

This is usually cured with just a click or two on the TX brake adjustment.
fatdoggy is offline   Reply With Quote
Old 08-05-2004, 05:10 PM   #39
Tech Master
 
Join Date: Mar 2004
Location: Earth
Posts: 1,039
Send a message via ICQ to rcnewb2004
Default

cool thx alot FD.

Btw, anyone know the cheapest place online to buy enduro brushes? my lhs is charing $5.50 for a set of sprint brushes.

I need somewhere that's going to get me some better prices!
rcnewb2004 is offline   Reply With Quote
Old 08-05-2004, 06:04 PM   #40
Tech Elite
 
Join Date: Jul 2004
Posts: 2,416
Trader Rating: 7 (100%+)
Default

$5.50 US? You're getting ripped off. Try any on-line shop, like Stormer or Tower. I don't think they have any bulk packs yet.
071crazy is offline   Reply With Quote
Old 08-05-2004, 07:30 PM   #41
Tech Master
 
Join Date: Mar 2004
Location: Earth
Posts: 1,039
Send a message via ICQ to rcnewb2004
Default

yea $5.50 is WAY too much.

I will check around for some brush packs.
Are the springs that come with this motor ok?
rcnewb2004 is offline   Reply With Quote
Old 08-11-2004, 01:30 AM   #42
Tech Master
 
Join Date: Mar 2004
Location: Earth
Posts: 1,039
Send a message via ICQ to rcnewb2004
Default

Is there any store online that is selling bulk packs of enduro brushes for the v2 motor?
rcnewb2004 is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Peak Racing (Vantage Touring 10x2 motor) cheap!!! fbass4u R/C Items: For Sale/Trade 5 01-06-2007 09:49 AM
Peak Vantage V2 endbell 10x1 CHEAP! Rogier R/C Items: For Sale/Trade 7 12-12-2006 02:52 AM
Where Can I find Full Specs on a Surikarn Edition V2 10X1 motor? rcnewb2004 Electric On-Road 3 08-21-2005 12:43 AM
Peak Vantage Surikarn Edition Evo_Uk R/C Items: Wanted to Buy 1 05-20-2004 01:37 PM
Looking for a Peak Surikarn Vantage amgman Electric On-Road 2 05-01-2004 01:46 AM



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 07:41 AM.


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