JR Propo DS9521HV Low Profile Digital Servo (Metal Gears)
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- All Purpose (Torque Type) High Voltage Servo.
- Features a metal gearset.
- Dual Ball Bearing.
- Servo Type: Digital High Voltage 6.0-8.5V.
- JR's HV servos are designed with motors and electronics that operate off the direct voltage of a 2-cell Li-Po, Li-Ion, or Li-Fe rx pack.
The DS9521HV is part of JR's range of high voltage digital servos. This high voltage low profile, high torque servo has been designed as an all aircraft/all purpose servo.
Battery chemistries such as Li-Po, Li-Ion, and Li-Fe have become very popular within the RC community. They are the standard for powering electric motors and have also gained popularity as receiver battery packs. The issue is the output voltage of these batteries is higher then the previous standard 4 - and 5-cell NiCd and NiMH packs, 4.8V and 6V respectively. The higher voltage is not an issue with the receivers but can be for the servos. Many servos will not operate at these higher voltages for very long before burning out the motors or electronics.
To get around this issue modelers have had to use a regulator to drop the voltage to an acceptable operating range for their servos, usually around 5 to 6 volts. The addition of a regulator adds a component that, should it fail, can cause the loss of a model.
JR's HV servos are designed with motors and electronics that operate off the direct voltage of a 2-cell Li-Po, Li-Ion, or Li-Fe receiver battery pack (6.6V to 7.4V nominal voltage). This eliminates the need for a regulator and lowers the chance for a power failure that can cause a catastrophic failure of your model. Also note that the HV servo specs are shown at the higher voltage (7.4V 2S LiPo) but will still operate on a standard 5-cell 6V NiCd, Ni MH battery with a reduction in performance of approximately 10% in speed and torque.
|Torque:||6.1Kg.cm (6.0v) / 7.6Kg.cm (7.4v)|
|Speed:||0.19s/60° (6.0v) / 0.15s/60° (7.4v)|
|Dimensions:||25.5 x 19 x 40.5mm|
|Operation Voltage:||6.0V - 8.5V|
JR Servos and 4.8v
JR design their range of servos around the voltage of a 4 cell Ni-Cd or Ni-Mh battery. These batteries are rated at 4.8v but this is a nominal voltage for the battery pack. A 4 cell battery will reach slightly over 6v when fully charged.
With modern Li-Po and Li-Fe batteries being widely used, regulated power supplies are becoming common place in model aircraft to help keep the weight down, keep a stable voltage and to aid in high power situations on large aircraft with high power servos. The use of a regulated power supply upto 6v is fine to use.
However using a 5 cell Ni-Mh battery which is rated at 6v is not ok to use, this battery will reach over 7v when fully charged and may damage the servo. If you are looking to use this type of battery we would recommend the HV, WV or NX range of JR servos which can handle this extra voltage.