Thursday, July 14, 2005 12:40 PM Augusto Yipmantin" wrote: > Hi all, > > Maybe this will be a fool question, but I want to know how to reduce the > velocity of a 48VAC little motor used by HAMS to rotate antennas. > > Regards, > > Augusto I'll start by describing the two types of rotors I have owned I'm sur ethere are many more systems out there. 1: the controll box at the rig has a synchronous motor of similar build as the one in the mast with the same gear ratio (mechanically or by number of poles) just smaller because not much torque is needed Both motors are in parallel and turn at the same time. on the motor is a cam that can depresses the microswitch for clockwise, none or the microswitch for counterclockwise rotation of the motor pair. adjustment of position is done by adjusting a dial that rotates the angle of two microswitches. The motor in the base unit and the motor in the mast both rotate untill none of the switches is pushed. this is the set position. the speed of the antenna is determined by the mains frequency and gearing. 2: the controll box is electronic the motor in the mast is a synchronous motor and rotates when ac mains is applied. current position is tracked by counting zero crossings up and down and comparing current value with set value. On the totally mechanical device gearing could be changed in the mast unit IF you also do the same with the base unit this would probably be very complex. you could reduce frequency of the AC (and reduce voltage at the same time). In the electronic version gearing would be easy to do but you would probably have to change software if you still want the entire 360degree rotation and correct display of the position. modification of the ac frequency and voltage may not be simple. Hope any of this helps understanding the issues involved. Peter van Hoof -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist