Eaton Industrial Switchgear - General Information

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• Have the switch positions marked “0” and “I”.
• Be lockable in the OFF position.
• Cover the connection terminals against accidental contact.
• Have a minimum switching capacity for load disconnectors and motor switches
for AC-23.
Mechanical shock resistance
The ability of a device to withstand pulse-like movement without changing its oper-
ating state or sustaining damage. No contact lifting must take place on devices in
the On position, the main contacts must not knock against one another in the Off
position. A circuit-breaker must not trip, and control circuit switches must not
change their switching state.
Minimum command time
Minimum period of time for which a trip-initiating factor (such as a control pulse or
a short-circuit current) must be present to cause the corresponding reaction, for
example the short-circuit duration necessary to initiate tripping.
Mirror contact
(cf. IEC/EN 60947-4-1 appendix F) A mirror contact is an auxiliary break contact that
can not be closed at the same time as the contactor's main make contacts.
Motor rating
(cf. IEC/EN 60947-1; 4.3.2.3) Motor output that can be switched by a switching device
at the assigned rated operational voltage, depending on the utilization category, e.g.
a contactor of utilization category AC-3: 37 kW at 400 V.
Opening delay
(cf. IEV 441-17-36) The interval of time between the specified instant of initiation of
the opening operation and the instant when the arcing contacts have separated in
all poles. The opening delay is the sum of the tripping delay and the inherent delay
of the contacts.
Overvoltage category
(cf. IEC/EN 60947-1; 2.5.60) Classification for prospective overvoltages at the point of
installation, such as might be caused by the effect of lightning or switching process-
es. The overvoltage category for industrial switchgear is III. According to the over-
voltage categories, the use of switchgear is permissible in the following areas:
Overvoltage category I:
Apparatus for connection to circuits with overvoltage protection, e.g. electronic
devices.
Overvoltage category II:
Consumers for connection to fixed installations, such as household appliances or
electrical tools.
Overvoltage category III:
Apparatus with special serviceability requirements for connection in fixed installa-
tions that are protected by overvoltage diverters, e.g. switches in low-voltage dis-
tribution systems or in control systems for industrial use.
Overvoltage category IV:
Use immediately at the the connection point of the installation (direct lightning
impact possible), for example on an overhead power line connection.
Pollution degree
(cf. IEC/EN 60947-1; 5.5.58) Classification for the likely amount of conductive dust
and humidity, which can lead to a reduced electric strength of a switching device.
The pollution degree is described by the following influencing factors:
Pollution degree 1:
If soiling occurs, pollutants are usually only dry or non-conductive. The soiling does
not affect electric strength.
Pollution degree 2:
Usually only non-conductive pollutants. Temporary conductivity due to condensa-
tion is to be expected, however.
Pollution degree 3:
(Switchgear for industrial use) Conductive pollution or dry, non-conductive pollu-
tion that is made conductive through condensation.
Pollution degree 4:
Pollution leading to continuous conductivity, for example conductive dust, rain or
snow.
Positive/enforced operation/actuation
This describes an arrangement where a mechanical link between the actuator and
the switching element ensures that the force exerted on the actuator is exerted
directly, onto the switching element, i.e. without the use of spring-loaded parts.
Positive opening
(cf. IEC/EN 60947-1; 2.4.10 / IEV 441-16-11) An opening operation which ensures that
the main contacts of a mechanical switching device have attained the open position
when the actuator is in the Off position.
Power disconnecting device
￫Main switch
Rated actuating voltage Uc
(cf. IEC/EN 60947-1; 4.5.1) Voltage applied to the actuation N/O contact in a control
circuit. May deviate from the rated control voltage due to the presence of trans-
formers or resistors in the control circuit.
Rated breaking capacity
(cf. IEC/EN 60947-1; 4.3.5.3) The r.m.s. value that a switching device is capable of
breaking according to its utilization category. This value refers to the rated opera-
tional voltage and the rated operational current. Equipment must be capable of
breaking of current up to and including its specified rated breaking capacity.
Rated conditional short-circuit current I q
(cf. IEC/EN 60947-1; 2.5.29/IEV 441-17-20) The short-circuit current that a switching
device, e.g. a contactor, protected by a short-circuit protective device, such as a
motor-protective circuit-breaker, can carry for the duration of the tripping delay of
the protective mechanism.
Rated control voltage Us
(cf. IEC/EN 60947-1; 4.5.1) The voltage applied to the input terminals of the control
circuit of a switching device. Due to the presence of transformers or resistors in the
control circuit, this voltage may differ from the rated control circuit voltage.
Rated frequency
(cf. IEC/EN 60947-1; 4.3.3) The frequency for which a switching device is designed
and to which the other characteristics relate.
Rated impulse withstand voltage U imp
(cf. IEC/EN 60947-1; 4.3.1.3) Measure of the stability of the internal clearances of a
switching device against overvoltage peaks. The utilization of suitable switchgear
can ensure that overvoltages are prevented from transferring from the mains to de-
energized system sections within it.
Rated insulation voltage Ui
(cf. IEC/EN 60947-1; 4.3.1.2) Voltage to which insulation tests and clearances relate.
The highest rated operational voltage must not be greater than the rated insulation
voltage.
Rated making capacity
(cf. IEC/EN 60947-1; 4.3.5.2).The current that a device is capable of making in accor-
dance with the utilization category and at the rated operational voltage.
Rated operational current Ie
(cf. IEC/EN 60947-1; 4.3.2.3) The current that a switching device is capable of
carrying, taking into account the rated operational voltage, duration of operation,
utilization category and ambient air temperature.
Rated operational current In (of a circuit-breaker)
(cf. IEC/EN 60947-2; 4.3.2.3) For circuit breakers, this current value is equal to the
rated uninterrupted current and the conventional free air thermal current.
Rated operational voltage Ue
(cf. IEC/EN 60947-1; 4.3.1.1) Voltage to which the characteristic values of a switch-
ing device relate. The highest rated operational voltage must not be greater than the
rated insulation voltage.
Rated service short-circuit breaking capacity Ics
(cf. IEC/EN 60947-2; 4.3.5.2.2) The short-circuit current that a circuit-breaker is able
to interrupt repeatedly; dependent on the rated operational voltage (test O-CO-CO,
previously P-2). After breaking the short-circuit, the circuit-breaker is able to carry
the rated uninterrupted current again with increased self-heating, and to trip in the
event of an overload.
Rated short-circuit breaking capacity Icn
(cf. IEC/EN 60947-1; 4.3.6.3) The maximum current that a switching device can break
at rated operational voltage and frequency without sustaining damage. It is
expressed as an r.m.s. value.
Rated short-circuit making capacity Icm
(cf. IEC/EN 60947-1; 4.3.6.2) The maximum current that a switching device can make
at a certain rated operational voltage and frequency without sustaining damage. In
contrast to other characteristic values, it is expressed as maximum prospective
peak value.
Rated short-time withstand current Icw
(cf. IEC/EN 60947-1; 4.3.6.1) The short-time withstand current that a device is capa-
ble of carrying for a specified time without damage, e.g. due to excessive heating.
Rated ultimate short-circuit breaking capacity Icu
(cf. IEC/EN 60947-2; 4.3.5.2.1) Maximum short-circuit current that a circuit-breaker
can interrupt (test O-CO; formerly P-1). After short-circuit breaking, the circuit-
breaker is able to trip in the event of an overload with increased tolerances.
Glossary of terms
Terms from IEC and EN