MAINTENANCE
INTERSTATER 03/09 Maintenance Section 5-6
© 2009 Alamo Group Inc.
MAINTENANCE

CUTTER UNIT

A. GENERAL
The INTERSTATER electrical circuit controls the flow of oil to the hydraulic motor on the cutter unit. The motor
control valve relies on a solenoid to control the spool within the valve and direct the flow of oil.
When the mower ON/OFF switch is in the "ON" position, current flows to the solenoid which positions the spool
to direct the oil flow from the pump to the motor. The oil then turns the motor which drives the cuttershaft.
When the mower ON/OFF switch is in the "OFF" position, the solenoid is not energized and oil pressure in the
power circuit pushes the spool back allowing the oil to return to the reservoir from the valve. Without the flow of
oil, the motor will no longer drive the cuttershaft.
B. OFF-ON SWITCH
The electrical circuit is connected to the tractor ignition switch. (See Electrical Schematic). The yellow wire
connects to the switch accessory terminal and the red wire connects to the start terminal. A 6 amp in-line fuse
on the yellow wire protects the off-on switches from an overload. THE OFF/ON SWITCH HAS A SAFETY
LOCK-OUT FEATURE THAT WILL NOT ALLOW THE TRACTOR STARTER TO ENGAGE IF SWITCH IS IN
THE ON POSITION.
C. SAFETY CUT-OFF SWITCH
In the electrical circuit between the OFF-ON switch and the motor solenoid valve is a safety cut-off switch.
This switch is a cam-operated electrical switch that cuts the wing mowers off when the wing is raised to
approximately 6 0 degree ang le. This also prevent s mower fr om being oper ated with th e wing up. This feature
prevents injury due to inadvertently starting mower with wing raised and should be kept in proper operating
condition.
D. SOLENOID OPERATED VALVE AT MOTOR
The electric solenoid valve is mounted in the hydraulic motor manifold block. The solenoid controls the spool
within the valve. When the off-on switch is on and the wing is lowered the soleno id in energized by electric al
current and the spool is closed to direct the flow of oil from the pump through the cuttershaft hydraulic motor.
The wing activates the safety cut-off switch, the electrical current is removed from the solenoid causing the
spool to open and allows oil to return to t ank witho ut being dire cted thro ugh the motor. Without oil flow through
the motor, the cuttershaft will not operate.

GENERAL MAINTENANCE

Mowing is accom plished by a series of knives which rotate at high speed on a shaft. The shaft is driven by a
hydraulic moto r th ro ug h a set of dr ive belts. Belt tension is maintained by a spring-loaded idler pulley.
The cutter unit is mounted to the lift frame by two mounting pins and held in place by a hydraulic cylinder. This
cylinder is used to tilt the cutter unit to allow mowing on an angle and tilting to the vertical position for
transporting. Another hydraulic cylinder is mounted to the lift frame and the lift cylinder support. This cylinder is
used to raise the cutter unit via the lift frame.
The cutter unit rides on a large roller assembly. The position of this roller is adjustable and will determine the
cutting height of the knives.