ABB Mechanism HMB-8, Instructions Manual

641P026-008

HMB-8 / HMB-8.7 Mechanism

© 

(formerly HMB-11)

Page 13

4 November 2005

8.

Add the hydraulic oil as in 4.3.6.1, Step 4. The total oil
volume capacity of the mechanism is approximately 2
liters (2.1 quarts).

9.

Close the oil drain valve 51013.

10. Break the vacuum.

11. Top off the oil, if necessary, using the procedure

described in 4.3.6.1.

12. Close the oil fill port and low pressure port.

13. Close the pressure equalizing valve stem 51017 by

rotating the black lever against the mechanism body.

14. Charge the HMB mechanism and operate it several

times.

Important:

After filling the mechanism with oil, allow it to
stand pressurized for at least 8 hours before
checking for leaks.  Refer to section 4.3.8.

Important:

When reattaching the mechanism cover
51028, torque the cover bolts to 3 Nm.

4.3.7

Replacing the Pump Motor

To replace the old pump motor 51002 (Fig. 1) with a new
pump motor:

1.

Remove the three screws holding the pump motor to
the cover 51023 (Fig. 5).

2.

Loosen the set screw holding the small bevel gear
51018 to the pump motor shaft.

3.

Install the small bevel gear onto the shaft of the new
pump motor but do not tighten the set screw.

4.

Install the new pump motor onto the cover 51023.

5.

Position the small bevel gear on the new pump motor
shaft so that there is small amount of play between the
small bevel gear and the large bevel gear 51019
through the entire rotation of the large bevel gear.

Important:

Be sure that the small bevel gear and large
bevel gear do not mesh too tightly to prevent
damage to the gears.

6.

Apply Loctite 242 to the small bevel gear set screw and
tighten.

7.

Replace the three screws holding the pump motor.

Important:

When reattaching the mechanism cover
51028, torque the cover bolts to 3 Nm.

4.3.8

Leak Checking the Hydraulic System

Notice:

Before checking for leaks, disconnect the
power to the pump motor to prevent the pump
from automatically starting.

Check for oil leaks while the breaker is in both the CLOSE
and OPEN positions.  This procedure takes approximately
24 hours in both the OPEN and CLOSE positions.

To check for leaks:

1.

Place the breaker in the OPEN position.

2.

Charge the mechanism fully.

3.

Record the travel of the disc spring assembly 51008
(Fig. 6) over a 24-hour period using a caliper.  If the disc
spring assembly discharges more than 20 mm over a
24-hour period when the breaker is either in the OPEN
or CLOSE position, contact ABB Service.

4.

Place the breaker in the CLOSE position and repeat
step 2.