Case Puma 170, 185, 200, 215, 230 CVT Tractor Repair Manual

Manuals: Service Manual
Introduction
Engine
Clutch
Transmission
Four Wheel Drive
Front Axle
Rear Axle
Power Take Off
Brake and Controls
Hydraulic Systems
Pneumatic System
Hitches, Drawbars and implement couplings
Frames and ballasting
Steering
Wheels
Cab climate control
Electrical System
Platform, cab, bodywork and decals
Manual Extract: Electric PTO Speed Shift

The electric shift system replaces the PTO speed selecting lever with a rotary three position switch to select the required PTO speed. The speed change switch is located near the right hand side C pillar of the tractor cab.

The electric speed selecting system replaces the control lever in the cab with a switch and motor coupled via a gearbox and worm drive system. The worm drive moves a carriage that has the Bowden cable attached to it, the motor can be driven in either direction using a H configuration relay drive system, so the PTO speed may be changed from low speed to N to high speed or vice versa as required. The motor drive system senses the current through the motor and has a Hall effect position sensor that is connected to the moving carriage within the electric shift unit.

To select the high PTO speed the motor is driven to a position approximately 200 A to D counts ( 0.97v or 19%) greater than the fully retracted position, acquired during the PTO shift mechanism calibration process; the drive current is also checked to ensure that it is lower than a preset level which occurs when the selector mechanism is in the detented position for the required speed.

To select the low PTO speed the cable is driven to a position approximately 200 A to D counts ( 0.97v or 19%) less than the fully extended position limit, acquired during the PTO shift mechanism calibration process, the drive current is checked to ensure that it is at or lower than a preset level which occurs when the selector mechanism is in the selected gear detented position.

Mechanical layout of the PTO speed change lever on the transmission case.