This Servo Gearbox is driven by the Hitec HS-788HB Sail Winch Servo, capable of rotating nearly 8 turns in stock form. This gearbox introduces a 4:1 external gear ratio in order to lessen the range while increasing the torque and precision by 4X. Having the servo mounted in the gearbox also isolates the load to a huge 32mm output hollow tube that is supported in a pair of bearings to protect the servo from any radial or axial loads. The gearbox opens up a world of mounting possibilities given the M4 threaded holes on each side which are on grid pattern for compatibility throughout the goBILDA system. The hub on the top of the gearbox provides threaded holes to fasten to, but you can also opt to fasten straight to the aluminum output gear using M4 hardware and standoffs or spacers.
If you’re not accustomed to using a servo gearbox, it’s just like a normal servo only larger. While the range and torque might be greater than the servos you’re used to, the control signal is identical. It will simply plug into an R/C receiver, an Arduino, Raspberry Pi or REV controller. Furthermore, since the Hitec servo hasn’t been modified in any way it’s FTC legal.
Note: The max travel is based on a the max PWM range. If your controller is not able to send the listed max PWM range, you can easily calculate the amount of travel with a different PWM signal range by multiplying the ‘travel per microsecond’ by the change in signal. For example, if you have a controller capable of 1000-2000 microseconds (μsec), your change in signal is 1000μsec. Since the 4:1 model rotates 0.39°/μsec, the total travel will be 390 degrees (1.1 rotations).
|Voltage Range||4.8V ~ 6V|
|Max Travel||1.96 Rotations (707˚)|
|Max PWM Range||600-2400μsec|
|No-Load Speed (6.0V)||0.93 sec/60˚ (65˚/sec)|
|Stall Torque (6.0V)||52.8 kg.cm (732 oz-in)|
|Direction||Counter Clockwise w/ Increasing PWM Signal|
|Travel per μsec||0.39˚/μsec|