Different specs for German TEU-302BK?

[Mouton]

I recently picked upp two TEU-302BK from Germany. Both the box and manual claims they can handle 17+ turns motors. I know all the other specs I have seen for this ESC says 23 turns. This implies that Dickie-Tamiya either made a mistake or that they have different specs. Can this be true?

[Larrio]

Our German agent *may have* tested the ESC and found that it can handle up to a 17 turn motor.

For Tamiya USA, we are still abiding by the original manual specifications of a 23 turn motor limit.

[Mouton]

Larrio, thanks for your thoughts.

You might be correct, in fact I presume that is the case that the German distributor have tested it to be ok with 17 turns. It does not really matter since one will go in a Tamiya Sand Scorcher and the other in a Tamiya Audi Quattro. Neither will handle a hot motor well so it will not put them to the test either.

Come to think of it I do have an old Novak ESC where the manual says 20 turns and the dealer and Novak's web site said 15.

Different specs would only be feasible for regulatory reasons (i.e. leadfree vs. leaded tin on the PCB).

[Larrio]

Sorry it took so long to respond! I was on vacation for a few weeks and missed out on a few posts.

I've tested the normal TEU-101BK up to a 15 turn in a TT-01. Although it did have some thermal shut-downs here and there (and the ESC got really hot).

If I get a chance to head to Nuremburg for the Toy Fair one of these days I'll be sure to ask the German agent.

[Gomjaba]

May I ask what "turn" actually means in conjunction with a Speed control ?

[McFig]

Our German agent...

Oh, you have agents? What other spys do you have? And what is their objective? Talk! or I'll make you talk. :LOL:

[Mouton]

Gombaja,that is a good question - especially since one needs to know about turns when buying and combining brushed motors and ESCs.

The short version:
Never combine an ESC with a motor that has fewer turns than the ESC is designed for. The number of turns on the motor must be higher (or at least equal) than what the ESC is designed for in order for them to work together.

The explanatory version:
Generally speaking two things decide how fast a motor is. How fast it spins when fed with 7.2 V (RPM) and torque (turns and winds), that is how well it can sustain the high RPM under load. Both are generally given by most manufacturers. You may have seen "15x2, 33 000 RPM", where 15 is the number of turns and 2 is the number of strands the wire has.

Turns refers to the number of times a wire is wrapped around the motor armature and winds is the number of strands the wire has. A lower number of turns translates to higher RPM (shorter wire, lower internal resistance). That makes them draw more current, thus beeing called "hotter" motors and a more difficult load for speed controllers. Moreover this also translates into different run-times, where a lower turn-motor has a shorter run-time than a higher-turn motor.

Winds have a similar effect on power and run-time. A single wind (x1) motor will give you more punch than a higher wind motor (say x3). The latter will give a smoother pickup and a slightly higer top speed. The more winds a motor has the lower its run-time will be given the same car and battery.

When combining a motor with an ESC the ESC must cope with the load the motor will apply. This translates to that the number of turns the ESC can handle must never be "exceeded" by using a hotter motor. Here is where it gets difficult as higher numbers are generally "better" (=faster). It is important to remember that the number of turns is related to internal resistance and higher resistance means a slower motor that put a lesser load on the ESC. Since "hot" is a keyword here it means that the motor turns must be equal or higher than what the ESC can withstand for it not to burn.

Thus, never combine an ESC with a motor that has fewer turns than the ESC is designed for. The number of turns on the motor must be higher (or at least equal) in order for it to work.

This explanation is simplified as other factors as the magnetic field, brushes, timing, friction and some other factors affect motors. Gearing and cooling are two other important factors. When going from a 20x2 to a 12x1 you are most likely to change gearing too, same goes for changing to much smaller/bigger tires. Hotter motors and ESCs made to cope with hotter motors (that han handle low-turn motors) need more cooling since they produce more heat. That is why some competition level ESCs have cooling fans.

Heat and speed are seldom a problem for "us threespeeders" as we rarely aim fo going as fast as possible with our models. I would dare say that few models featured in the gallery here have motors with fewer than 20 turns. A "threespeeder's" main concern is typically the ESCs ability to provide sufficient current to the servos (BEC) when they go for ultra high-torque steering servos in their off road threespeeders with huge tires.

I hope it might help clear things up when you will match a motor to an ESC the next time.

[Gomjaba]

:yourock:

Thanks a lot. Nice explanation indeed !!!!:first:

[Larrio]

awesome post.