----- Original Message ----- From: "Mike Hoblinski" hobergenix@sbcglobal.net To: amsat-bb@amsat.org Sent: Sunday, April 28, 2013 7:55 AM Subject: [amsat-bb] G5500 Rotor motor Question
Anybody know what the rpm of the AC motors are. I know from the Yaesu specs that after all of the gear reduction they list EL as 67 seconds for EL and 58 Seconds for AZ.
I would like to experiment with an AZ and EL system but like to see what RPM the motor starts out with and how much torque to get the final results. They show Elevation at 101 FT-LBS and AZ at 44 FT-lbs.
I have looked around to see if somewhere the specs are available for the motor but have had no luck. I have seen quite a few pictures of rebuilds of that rotor with part number and have a manual that shows parts.
Mike Hoblinski
N6IMF
Hi Mike, N6IMF
The EL and AZ motors of a G5500 rotator are 2 pole (P) squarrel cage AC asynchronous motors because the stator is wound with 4 coils and each couple of 2 coils is positioned 90 degrees with respect to the other couple of 2 coils.
The RPM (revolutions per minute) of a asynchronous motor is given by the following formula:
f x 60 RPM = ------------- - S P
where:
f = value of the frequency in Hz of the supply AC power 60 = 60 seconds into a minute P = number of poles of the motor S = speed of gliding ( 7 % for small motors )
If you supply the motor with 24 volt 60 Hz as in USA than
60 x 60 RPM = -------------- = 1800 - 7% = 1674 2
I hope this helps.
73" de
i8CVS Domenico