
2 Engineering
2.8 Switch-disconnectors
DB1 variable frequency drive
11/20 MN040031EN
Eaton.com
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2.8 Switch-disconnectors
Switch-disconnectors are used as repair and maintenance switches in indus-
trial, trade, and building service management applications. At the output of
variable frequency drives, they are primarily used to locally switch off motors
(pumps, fans) that pose a risk of unintended starting during maintenance or
repairs. In order to provide greater safety, these switch-disconnectors can be
locked out with the use of padlocks, meaning they have characteristics com-
parable to those of main switches as defined in EN 60204.
Eaton T0…/MSB/…, P1…/MSB/…, and P3…/MSB/… enclosed switch-dis-
connectors are designed for local installation with an IP65 degree of protec-
tion. The internal screening plate ensures that screened motor cables can be
easily connected in a way that meets EMC requirements.
The switch-disconnectors on the output side of a DB1 variable frequency
drive need to be sized based on utilization category AC-23A (IEC/EN 60947-3)
for the assigned rated motor current and the corresponding rated operating
voltage.
When a motor is being switched off, the DB1 variable frequency drive’s
output (inverter) must be disabled (the FWD/REV enable signal must be
switched off) before the contacts are opened.
For more information and technical data on T0…/MSB/…,
P1…/MSB/…, and P3…/MSB/… switch-disconnectors,
please refer to instruction leaflets IL008020ZU and
IL008037ZU.
WARNING
Switching off during operation in vector mode (P-60 = 0 / 2 / 3 / 4)
is not permissible and may result in damage to the switch-dis-
connector and the variable frequency drive.
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