M ED I U M VO LTAG E P R O D U C T S
37
37
8.3. Operating life
All vacuum circuit breakers are characterised by
simple, sturdy construction and long useful life.
Frequent operation of the service and short-circuit
currents does not negatively affect the degree of
vacuum of the interrupters.
Typical useful life expectancy of a VM1 vacuum
circuit breaker is determined by the following
factors:
•
embedded vacuum interrupter, maintenancefree up
to 30,000 mechanical operating cycles.
•
drive with magnetic actuator, maintenance free
under normal service conditions
- up to 100,000 operating cycles for all the circuit
breakers with breaking capacity up to 25 kA
- up to 50,000 operating cycles for all the circuit
breakers with breaking capacity 31.5 kA
• control module and sensors, maintenance-free
(excluding the auxiliary contacts)
•
indication of ON/OFF position of the auxiliary
contacts (optional) up to 30,000 operating cycles
•
withdrawable truck: up to 1000 handling operations
can be carried out in the case of normal activation
and with regular inspections.
The data on the useful life are in principle applied to
all the components which are not directly affected
by the operator.
The useful life of the manually activated
components (movement of the withdrawable truck,
etc.) can vary according to the type of handling.
The time intervals and amount of maintenance are
determined by environmental agents, by the
frequency of operation and by the number of trip
operations under short-circuit.
8.4. Instructions for capacitor life
The following instructions shall be observed in
order to guarantee the correct function of the
capacitor/s over time:
•
if the capacitor is kept on stock or warehouse for
more than 2 years without power supply feeding, it
is required to replace the capacitor.
•
if the capacitor is kept on stock or warehouse for
more than 1 year and less than 2 years in/out of
temperature tolerance range (-25 °C to +55 °C), the
reconditioning procedure of the capacitance by
reforming must be executed.
•
it is recommended to replace the capacitor every 10
years for both normal and stressed use (10000
operations) and for conditions of temperature
within -25 °C to +55 °C.
•
after 15 years the capacitor must be replaced.
•
for applications in which the capacitors are installed
in parallel (two, three or more), they should belong
to the same production batch hence to have the
same batch number YYWWXXXXX (QR-CODE).
8.5. Procedure for discharging the
capacitor/s
Before accessing the circuits in the control box, it is
compulsory to make sure that the capacitor is
discharged. Even without auxiliary power supply,
more than about ten minutes are needed to
completely discharge the capacitor/s.
Activate the circuit breaker.
Disconnect the power supply voltage.
Operate the circuit breaker by pressing the
pushbuttons with the following cycle: O-C-O.
The luminous “Ready” signal turns off when the
operation cycle has been completed, i.e. when the
circuit breaker is no longer ready for operations.
After 10 minutes have passed, the capacitor voltage
drops to a value of less than 15 V.
It is avalaible on request the Rapid Discharging
Device that allows the waiting time to be reduced to
just one minute and guarantees safe access to the
circuits which might be live.
Summary of Contents for VM1/A/P
Page 49: ...MEDIUM VOLTAGE PRODUCTS 49 49 ...
Page 51: ...MEDIUM VOLTAGE PRODUCTS 51 51 ...
Page 53: ...MEDIUM VOLTAGE PRODUCTS 53 53 ...