Moog 62 Series Installation And Operation Instruction

1. INTRODUCTION

This manual provides instructions and procedures necessary
to install, operate and troubleshoot the Moog Series 62 Electrohydraulic
Industrial Servovalve. Troubleshooting instructions are outlined to permit the
identification of the specific component(s) suspected of failure.

2. OPERATION

The Moog Series 62 Electrohydraulic Servovalve consists of an electrical
torque motor, a nozzle-flapper pilot stage and a sliding spool main stage (see
Figure 1). The torque motor includes coils, polepieces, magnets and an armature.
The armature is supported for limited movement by a flexure tube. The flexure
tube also provides a seal between the hydraulic and electromagnetic portions of
the valve.
The flapper attaches to the center of the armature and extends down,
inside the flexure tube. A nozzle is located on each side of the flapper so that
the flapper motion varies the nozzle openings. Pressurized hydraulic fluid is
supplied to each nozzle through a filter and inlet orifice. Differential pressures
caused by flapper movement between the nozzle are applied to the ends of the
valve spool.
The 4-way valve spool controls flow from the supply to either control
port (A or B). The bushing contains flow control ports that are uncovered
by spool motion. A feedback wire is deflected by spool movement so that
feedback torque is applied to armature/flapper.
Electrical current in the torque motor coils causes either clockwise or
counterclockwise torque on the armature. This torque displaces the flapper
between the two nozzles. The differential nozzle pressure moves the spool to
either the right or left. The spool continues to move until the the feedback
torque counteracts the electromagnetic torque. At this point the armature
flapper is returned to the center, so the spool stops and remains displaced until
the electrical input changes to a new level. The actual flow from the valve to
the load will depend upon the load pressure.
CAUTION
DISASSEMBLY, MAINTENANCE, OR REPAIR OTHER THAN IN ACCORDANCE WITH THE
INSTRUCTIONS HEREIN OR OTHER SPECIFIC WRITTEN DIRECTIONS FROM MOOG WILL
INVALIDATE MOOG'S OBLIGATIONS UNDER ITS WARRANTY.
62 Series Installation and
Operation Instruction
Electrohydraulic Servovalve
ELECTROHYDRAULIC VALVE CUT-AWAY
Torque
Motor Coil
Upper Polepiece
Armature
Flexure Sleeve
Nozzle
Feedback Wire
Spool
Inlet Orifice
Filter Tube
P A
Figure 1 Moog Series 62
Flapper
Plug
Electrical
Connector
R B