MMP able to handle this Motor?

[outlaw]

Patrick,

you are the "Pro" here
Let me kindly ask you, why you suspect this ?

The motor we were talking about is a Tenshock 2240

22mm Rotor diameter 40mm long

I have a 5T = 3100kv

drkdgglr does have the 2240 as well, just 10T = 1560KV

The theard starter is talking about the 2220/6
Same typ of motor, just an 20mm long rotor.

Don't get me wrong ! I love your products and they are always first choice.
Can't wait to get a Mamba XL in my hands;-) to fill up my Castle collection

[Pdelcast]

Originally Posted by outlaw

Patrick,

you are the "Pro" here
Let me kindly ask you, why you suspect this ?

The motor we were talking about is a Tenshock 2240

22mm Rotor diameter 40mm long

I have a 5T = 3100kv

drkdgglr does have the 2240 as well, just 10T = 1560KV

The theard starter is talking about the 2220/6
Same typ of motor, just an 20mm long rotor.

Don't get me wrong ! I love your products and they are always first choice.
Can't wait to get a Mamba XL in my hands;-) to fill up my Castle collection

Generally, when designing a motor, the motor designer tries to maximize torque per amp/turn. The more torque the motor makes per turn, the more copper can be put into the motor per turn.

We are testing a Castle version of a 2622/1Y (28mm can outside diameter, 48mm can length) motor right now -- it's four pole, and 4200Kv with just 1 turn.
It's a 26mm diameter stator, with a 22mm length.

A 1 turn motor crams a TON of copper into the motor per turn -- yielding low resistance and giving high efficiency.

Lots of turns means less space for copper (per turn), and much higher copper losses in the motor (due to high resistance.)

Also, high pole count and high RPM usually don't work well together. Higher commutation speeds means higher iron losses.

The combination of high pole counts, and high turn count, just doesn't seem to make good engineering sense.

A 2 pole lehner 1940/10 also has approx. 1560kv. These are considered as good motors. Does the same rule apply here or are you specifically questioning the 6pole design?

btw, mine runs at 5s=28000rpm

[Pdelcast]

Originally Posted by drkdgglr

A 2 pole lehner 1940/10 also has approx. 1560kv. These are considered as good motors. Does the same rule apply here or are you specifically questioning the 6pole design?

btw, mine runs at 5s=2800rpm

Yeah, but the Lehner has the advantage of being a 2 pole. This means that the windings are less critical during forming, and generally low losses in the delta connection.

I just don't see the advantage of a 6 pole slotless motor. I haven't seen one (yet) that comes close to the efficiency of a slotted motor (except the Kontronic Tango - -which is a VERY interesting design...)

Slotless motors have some advantages over slotted motors:

1. Slotless motors have more room for copper in the winding.

2. Slotless motors have very low inductance, which means they are easier to start sensorless.

3. Slotless motors have lower iron losses (due to large air-gap.)

4. Tuning Kv is easier (because of the high turns count -- the differences per turn are small.)

5. Tooling for slotless motors is very inexpensive (in the $5000USD range -- vrs around $50,000USD for a slotted motor -- this is why there are so many slotless motors coming from China -- it's cheap and easy to get started in slotless motors.)

6. Because of the large air-gap, much cheaper steel can be used in a slotless motor without a large penalty in efficiency.

and some disadvantages:

1. Slotless motors generate a lot less torque per turn, and as a consequence, have higher resistance than a slotted motor at the same kV.

2. The windings for a slotless are more difficult to form correctly, so the performance of a slotless motor varies more from motor to motor than with slotted motors.

3. The efficiency of a slotless motor is generally lower than a slotted motor of equal weight and kV, in low to medium RPM applications, due to higher copper losses.

In general, slotless motors work well for low pole count, low torque, very high RPM applications. Slotted motors work well for higher pole count, high torque, medium RPM applications.

This is why I question the high pole count, medium RPM, high turn slotless design. I just haven't seen one (yet!) that works well.

That doesn't mean that this motor doesn't work well - - they may have an outstanding motor. I haven't had an opportunity to test one yet (I haven't even seen one yet!) It's just that in my experience, that kind of design is generally lower performance than a slotted design of the same weight and kV.

[outlaw]

The motors work really well !

I have a bunch of them here...

Patrick,

i will send my Mamba Monster for repair to you guys soon, i could put a motor in the shippment to your att if you like

How can I tell if the motor is slotted or slotless? (excuse my noobiness)

[outlaw]

First one
Slotless Lehner 1950/8

Second one
Slotted TS 2240/6

[outlaw]

Patrick,

thanks a lot