Replacement Of Components; Tests On Withdrawable Parts Withvm1 Type Circuit-Breaker; Motor-Driven Withdrawable Parts; Checking The Auxiliary Switch Settings On Withdrawable Parts - ABB VM1 Instruction Manual

7.4.2

Replacement of components

- Only remove and reassemble circuit-breaker parts and ac-
cessories when the breaker has been switched off and the
working area is to be isolated and secured against reclos-
ing.
- All supply voltage sources must be dis connec-ted and
secured to prevent reconnection during the removal and
installation work.
- The storage capacitor is to be discharged in accordance
with the instructions in section 7.1.
1. Circuit-breaker control unit:
Replacement of the circuit-breaker control unit may only be per-
formed by ABB after-sales service staff or specially trained skilled
personnel. Reason: the internal sequence times for the control unit
are set by jumpers on each control unit.
2. Withdrawable assembly:
(Figures 9/8, 9/10, 9/27 and 9/28)
- Disconnect plug connector 37.
- For motorized withdrawable assemblies, remove the two
socket head bolts (M4) which are accessible from below
the assembly.
- Unbolt the circuit-breaker from the withdrawable assembly
(4 x M12 bolts).
- Mount the circuit-breaker on a new with drawable assembly
in the reverse order.
- Check the settings of the slide blocker 41.2:
- The circuit-breaker is in the ON position.
- The distance between pawl 35.5 on the withdrawable
assembly and slide blocker 41.2 must be 0.1
If a correction is necessary, the screw 41.5 has to be
released and the slide blocker 41.2 has to be adjusted by
a feeler gauge. Thereafter the screw must be fixed again.
7.5 Tests on withdrawable parts with VM1 type
circuit-breakers
The following conditions are to be checked to test the function of
the withdrawable part.
7.5.1

Motor-driven withdrawable parts

(non-standard)
Inspection of motor-driven withdrawable parts should be per-
formed as for manually operated withdrawable parts in
accordance with Section 7.5.2:
- Turn off the supply voltage (m.c.b.), since the motor could
otherwise be braked electrically.
- Turn hand crank 38 in the required direction
(see Figure 9/21).
Note:
When the withdrawable part moves, the motor turns. The motor
functions in such a case like a generator, i.e. it can lead to reverse
voltages in the terminals.
18 VM1 Vacuum circuit-breaker | Instruction manual 504/05
7.5.2 Checking the auxiliary switch settings on withdrawable
parts
(Figures 9/10 and 9/21)
Compliance with the interlock conditions in the test/disconnected
and service position areas is ensured by position signalling
switches -BT2 and -BT1 located in the withdrawable assembly
and factory-set.
In test operations, the withdrawable part must be moved by hand
with the crank fitted with the motor power switched off.
1. Settings in the area of the test/disconnected position:
- Move the withdrawable part out of the test/disconnected
position towards the service position with a few turns of
the crank.
- Slowly move the withdrawable part back to the stop.
- Auxiliary switch -BT2 must then switch over just before
the stop is reached.
- Slowly insert the withdrawable part from the test/discon-
nected position towards the service position until auxiliary
switch -BT2 just operates (approx. 30° rotation of the
crank).
- It is no longer possible to switch the circuit-breaker on in
this position.
- When the hand crank is turned further, the position of the
circuit-breaker is polled by pawl 35.5 after a total angle
of turn of approx. 90°. If the circuit-breaker is closed, the
withdrawable part cannot be moved any further.
- For this test, the function of the blocking magnet -RL2
(if fitted) must be disabled manually.
mm. 2. Settings in the area of the service position:
+ 0.4
- Move the withdrawable part out of the limit position to-
wards the test/disconnected position with a few turns of
the crank.
- Slowly move the withdrawable part forwards again to the
stop:
- Auxiliary switch -BT1 must then switch over just before
the stop is reached.
- Slowly move the withdrawable part out of
the service position towards the test/disconnected position
until auxiliary switch -BT1 just responds (approx. 30° rota-
tion of the crank).
- When the hand crank is turned further, the position of the
circuit-breaker is polled by pawl 35.5 after a total angle
of turn of approx. 90°. If the circuit-breaker is closed, the
withdrawable part cannot be moved any further.
7.5.3 Checking the direction of rotation of the travel motors
on motor-driven withdrawable parts
- Move the withdrawable part by hand into a central position
between the test/disconnected position and the service
position.
- Remove the hand crank.
- Switch the supply voltage for the travel motor on.
- Use the local electrical controls to check that the withdraw-
able part moves in the correct direction.