MTS Series 252 Servovalves - Manual (Page 37)

Adjust the Mechanical Null
Series 252 Servovalve Product Information Maintenance 37
Do not apply more than 1.36 N•m (12 lbf-in.) of torquing force to the adjustor
pin.
Excessive torquing may shear off the adjustor pin eccentric.
If the pin does not turn using very little force, gently loosen the self-locking nut
more, then try turning the pin again.
C. Check that the scribe mark on the adjuster pin is pointed toward the
base (oriented in the lower 180° of the adjustment range). If necessary,
rotate the adjuster pin so that the scribe mark is pointed towards the
base.
D. While monitoring the command and feedback signals, slowly rotate the
adjustor pin until command equals feedback.
E. Verify that the scribe on the adjuster pin is pointed approximately
towards the base.
Mechanical Null Adjustor Pin
F. While holding the adjuster pin in position, tighten the self-locking nut
until it is snug, (1.13 to 1.35 N*m, 10 to 12 in*lbf) while monitoring
the command and feedback signals to ensure that the command equals
feedback.
CAUTION
Series 252.2x, 252.4x, and
252.5x
Servovalves
3/8 inch
Series
252.3x
Servovalve
3/32 inch
3/8 inch
3/32 inch
Adjuster Pin
Adjuster Pin
Scribe mark on adjuster pin
points toward base of
servovalve to mark the
approximate null position.
Self
Locking
Nut
Base
(Side View)
Base
(End View)