Installation And Precautions for Orbital Hydraulic Motors

When installing orbital hydraulic motors for manufacturers, we often receive customer complaints about substandard motor performance. However, analysis reveals that improper usage practices are widespread in actual applications, leading to suboptimal performance or damage.

Installation

(1) The mounting bracket for orbital hydraulic motors must possess sufficient rigidity. The motor must not vibrate under system pressure shocks to prevent damage.

(2) The motor output shaft must maintain coaxial alignment with the connected coupling.

(3) When using steel pipes for inlet and return oil connections:

  - All pipeline stresses must be completely eliminated to ensure no external forces act on the motor

  - Return oil resistance should be maintained below 0.3MPa for drain pipes

  - Return pipelines must be independently connected to the tank and must not be connected in series with other return pipelines

  - Excessive back pressure will degrade motor performance

Pre-operation preparation:

Prior to initial startup, fill the motor casing with clean hydraulic oil through both ports. Rotate the output shaft manually to verify smooth operation before installation.

Important notes:

- Radial loads on the output shaft must not exceed specified limits to ensure operational reliability and service life

- Replace hydraulic oil and clean filters after approximately 200 hours of operation

System Design

(1) Working pressure definitions:

  - Intermittent working pressure: Maximum pressure at inlet port

  - Continuous working pressure: Pressure differential between inlet and return ports

(2) Avoid simultaneous operation at maximum speed and maximum pressure

(3) Under intermittent working conditions:

  Motor running time must not exceed 10% of total cycle time per minute

(4) Maximum oil temperature: 80°C

(5) Back pressure management:

  - Standard shaft seals can withstand high pressure

  - Recommended maximum back pressure: ≤5MPa for optimal service life

  - For back pressure exceeding 5MPa, install external drain pipe while ensuring:

    a) Motor remains oil-filled

    b) Drain pipe maintains low back pressure

    c) Provides contaminant discharge and cooling(6) Run-in procedure:

 

(6) Run-in procedure:

  Operate at ≤30% of maximum working pressure for 1 hour before full-load operation

Precautions

1. High viscosity oil in cold conditions may cause pump cavitation (note: affects pumps but not motors)

2. Hydraulic oil selection criteria:

  - Consider all system components

  - Optimal viscosity range: 100-150 SUS (20-32 cSt)

  - Absolute minimum: 70 SUS (13 cSt)

  (Typical requirement for systems combining medium piston pumps with orbital motors)

3. Oil discoloration indicators:

  - Blackening: Potential overheating

  - Emulsification: Water contamination

4. Monitor fluid level indicators during low-temperature system operation