Manual 82510
Magnetic Pickups and Proximity Switches
Woodward
11
Troubleshooting Magnetic Pickups
Disconnect the pickup leads. Check between leads with an ohmmeter for resistance as listed below.
Check between the pickup case and leads with an ohmmeter for near infinite resistance. Start the prime
mover and control speed manually or block the throttle. Check pickup leads with a high-impedance ac
voltmeter for 10 to 20 V (ac, rms). Reconnect the pickup and check the speed sensor input terminals for a
minimum 1.5 V (ac, rms) at the lowest controlling speed. Check the pickup and gear clearance if voltage
is low.
MPU Resistance List
Long Standard Model
250
Ω
max
Extra Long Standard Model
250
Ω
max
Short Standard Model
220
Ω
max
Standard Metric Model
250
Ω
max
Conduit
Model
114
Ω
to 140
Ω
Explosion Proof Model
165
Ω
to 225
Ω
(also applies to SIL)
Inspect for physical damage. Replace pickup if faulty.
Released
