KL7UW

SPEED-CONTROL for the Ham-IV Antenna Rotator

Under Construction This page describes the construction of a speed control for CDE Ham series rotators such as Ham-IV. This is base on an article in Ham Radio Magazine, Jan. 1981, by Watson Gabriel, WB4EXW with a few minor changes. The basic ckt uses two NE555 timers to pulse a Triac to chop the 30 Vac power supplied to the rotator motor. The triac pulse-position controls the motor in the rotator by delivering short duration full voltage pulses to slow running of the motor with no loss of torque or heating of the motor. Full details are given in the article. The original article made modifications to a CDE control box. I have changed it to a separate control box which only uses 30vac from a CDE Controller. I discovered that the rotator brake presents a 5 amp load and the motor a 2.25 amp load which far exceeded the 25.6 Vac, 3 amp transformer I originally chose to power the speed controller. So I made provision for external source of 30 Vac (which I took from another CDE Control Box). (more to follow)

  • Schematic Diagram
  • Photos:

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