ABB ACS880-77CC, Руководство по оборудованию

Страница: 117 / 128

Planning the cooling system
￭
Connection to a cooling unit
General requirements
Equip the system with an expansion tank to damp pressure rise due to volume changes
when the temperature varies. Keep the pressure within the limits specified in section
Specifications (page 121) . Install a pressure regulator to ensure that the maximum permissible
operating pressure is not exceeded.
Install a bleeding valve at the highest point of the cooling circuit. Bleeding valve is not
included in the ABB converter delivery as standard.
The materials used in the cooling system are listed in section Specifications (page 121) .
Coolant temperature control
The temperature of the coolant in the internal cooling circuit must be kept within the limits
specified in section
Specifications (page 121) . Note that the minimum temperature depends
on ambient temperature and relative humidity.
The following diagram shows an example of coolant temperature control using the three-way
valve in the external cooling circuit. Part of the infeed coolant flow is directed into the return
pipe through a three-way valve without letting it circulate in the internal cooling circuit if the
coolant in the internal circuit is too cold.
„
TC
1 2
3
4
Internal circuit 1
External circuit 2
Infeed 3
Return 4
Cooling and heating 117