Honeywell HVAC232 Series, Applications Manual

Page: 116 / 145

Application manual HVAC232/402 | Document 27-652 | Issue ENG06 | 2019-08-07 116
Start DC current time
DC-brake is activated when the start command is given. This parameter
defines the time for how long DC current is fed to motor before acceleration
starts. After the brake is released, the output frequency increases according
to the set start function by par. 2.2.
Par 4.12
Par 4.9
t
DC braking current
Output
frequency
RUN
STOP
Fig. 55. DC braking time at start
External brake: Open delay
External brake: Open frequency limit
External brake: Close frequency limit
External brake: Close frequency limit in reverse
External brake: Open / close current limit
External brake control is used for controlling a mechanical brake on the mo-
tor by digital / relay output by selecting value 17 for parameters P8.1, P8.2
or P8.3. Brake is closed while relay is open and vice versa.
Opening brake conditions:
There are three different conditions for opening the brake, all must be true,
if used.
1. The Open frequency limit (P4.16) must be reached.
2. When the Opening frequency limit has been reached the Open delay
(P4.15) must also elapse. Note! The output frequency is held at the
Open frequency limit until this.
3. When the two previous conditions are reached. The brake will open if
the output current is higher than the current limit (P4.19).
Notice that any of the previous conditions can be left out by setting their
values to zero.