MTD 464 Betriebsanleitung PDF herunterladen (Seite 88)

ARMY TM 9-6115-464-34

AIR FORCE TO 35C2-3-445-2

NAVY NAVFAC P-8-624-34

(12) After Element No. 3 has tripped, connect the VOM between pins F and J to check for continuity.

Continuity should exist after Element No. 3 has tripped.

(13) Slowly decrease shaft speed while monitoring pin D with the VOM for voltage. There should be 24

volts present, dropping to 0 volts when Element No. 2 resets. “Reset speed” for Element No. 2

should be no more than 100 RPM below the trip speed noted in step (10).

(14) Continue decreasing shaft speed while measuring for continuity between pins A and C with the VOM.

Continuity should exist between these two pins until Element No. 1 resets, then an open circuit

should exist. Reset speed for Element No. 1 should be no more than 100 rpm below the trip speed

noted in step (6).

(15) Decrease shaft speed to 0 rpm. Monitor pin H for voltage with the VOM. Element No. 3 should still

remain in the tripped condition, resulting in 0 volts on pin H, and continuity between pins F and J.

(16) Depress and release the reset switch, S1, on the speed switch. Pin H should now read 24 volts on

the VOM, and an open circuit should exist between pins F and J.

NOTE

There are no repair or adjustment procedures for the electronics and base assemblies.

If this portion of the speed switch is malfunctioning, replace both assemblies as a unit.

k. Testing (Mechanical Type).

(1)

(2)

(3)

(4)

(5)

(6)

Connect a variable speed drive device to the speed switch drive. The drive device must have a

tachometer in order to determine the speed of the device in rpm’s.

With an ohmmeter on the R1 scale, reading from the speed switch connector, check for the contact

conditions of elements S9-1, S9-2, and S9-3 illustrated in figure 3-16, sheet 2.

When contact conditions are verified, as shown in figure 3-16 sheet 2, start variable drive and

gradually increase speed, with ohmmeter connected to pins B and A. At a speed of 290 rpm the

ohmmeter should indicate that contact A-B opens. Hold the variable speed drive at that speed and

transfer the ohmmeter leads to pins A and C. The ohmmeter should indicate a closed contact.

Leave the ohmmeter leads connected to pins A and C and gradually reduce speed. In the range of

190 to 210 rpm, the contacts of element S9-1 should reset to the condition illustrated in figure 3-16,

sheet 2. To verify operation of element S9-1 contacts A and C, increase drive speed gradually and

observe that the contacts close in the 290 to 310 rpm range.

Connect ohmmeter leads across pins D and E and verify an open circuit. Increase drive speed and

observe that element S9-2 (contacts D and E) closes in the speed range of 590 to 610 rpm (Mode l),

825 to 850 rpm (Mode II). Gradually reduce speed to 490 minimum rpm (Mode l), 725 minimum rpm

(Mode II). Observe that element S9-2 resets to the condition shown in figure 3-16, sheet 2.

Connect ohmmeter across pins H and G and verify a closed circuit. Increase drive speed gradually.

The contacts should open at a speed of 1200 to 1225 rpm. Hold drive speed and read contacts F

and J. Meter should indicate a closed circuit. Reduce drive speed to less than 1000 rpm, press the

manual reset switch and observe with the meter that element S9-3 contacts reset to the condition

shown in figure 3-16, sheet 2.

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