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Installation:
Mount the SW-50 to a secure bracket off the engine. If on-engine mounting is
necessary, shock mounts are recommended. Wire according to connection
diagram on reverse. Shielded cable is recommended. Shield should be brought
to ground directly. The SW-50 will work with most magnetic pickups provided
the signal amplitude is greater than 50 mVrms and less than 70 Vrms. Mount
pickup according to manufacturer’s instructions.
Calibration:
Determine the setpoint frequencies from an RPM value using the following
formula:
Verify current calibration:
Connect a signal generator
— such as the Dynalco F-16 — to the SW-50
magnetic pickup input (signal input).
Set the signal generator to a low frequency. Slowly increase the frequency.
Using an ohmmeter across each relay contact, in turn,
determine the frequency
at which the relays change state. (Note: overspeed relay will latch if terminal 4
is not grounded.)
Change the setpoints:
Remove the screws in the access holes for the relay adjustment trim pots.
Set the signal generator to the frequency at which the relay should change
state.
Using a small, flat screwdriver, adjust the trim pot for the appropriate relay until
the relay changes state.
Decrease the frequency, and then slowly increase it to verify that the relay trips
at the appropriate point.
