Maximum RPM's on Ammo Motors?

[Meniscus]

Does anyone know what the maximum RPM's are on Ammo motors? I haven't been able to locate those specs anywhere. I've been looking at some of the smaller diameter motors, long versions.

I appreciate the help! :smile:

[Diegoboy]

Your "little" Ammo motor 26-45-2700 have a set of specs that are as follows:

SPECS: Motor Diameter: 1.1" (28mm)
Motor Length: 1.77" (45mm)
Motor Shaft Diameter: .125" (3.175mm)
Motor Shaft Length: .6" (15.25mm)
Wire Length: 2" (52mm)
Mounting Hole Diameter: .09" (2.5mm)
Between Mounting Holes: .51" (13mm)
Weight: 4.6oz (133g)
RPM/V (kV): 2700kV
Resistance: .37ohms
Maximum Constant Watts: 518W
Maximum Surge Watts: 925W
Maximum operating temperature: N/A
Maximum RPM: N/A
Magnet: Neodymium
Input Voltage: 7.4V-18.5V
No Load Current: 1.5A
Max Constant Current: 28A
Max Surge Current: 50A
Prop Range: 8x6E-14x7E

[Meniscus]

Thanks for the info Diego, but I'm looking at a different one. In any case, I don't see maximum RPM, only input voltage.

Looking at the 24-45-3790 (http://www.electrifly.com/motors/motors-ammo-24-45.html)

[Diegoboy]

Max input voltage is 11.1V x 3790 = 42,069RPM is a MFG safe speed. so I'd say the max might be close to that number?

[Meniscus]

That's what I'm hoping. ...Now to fit a larger ESC in the Renegade, LOL!

....or maybe it's for something else.... :noidea:

:laugh:

[Brushless55]

Most brushless motors have a max rpm of about 60k

[sailr]

differs between 2 pole, 4 pole, 6 pole motors also.

[Fluid]

Typically motor rpm is limited by the quality of the bearings, then by the mass of the rotor/magnets (or how well they are glued to the rotor). By tying the magnets to the rotor with kevlar line this limit can be raised.

Examples: the large Lehner 3000 series 2-pole motors have an rpm limit of 50,000 rpm. The similar-sized Neus 2200 motors are limited to 40,000 rpm. The smaller 1500 series Neus are limited to 60,000 rpm. All those limits are regardless of the Kv or voltage.

My question to the OP - how will you know the rpm in use? Will you have a data logger? Knowing the Kv is much more useful than knowing the max rpm. Except for SAW applications you will never want to run a motor at 40,000 rpm or higher. Most props don't get much bite at that blade speed and are not very efficient.



.