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Protections (Control Panel: Menu Par  P12) - Honeywell HVAC232 Series Applications Manual

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10.11 Protections
(Control panel: Menu Par
Stall protection
0 =
No action
1 =
Alarm
2 =
Fault, stop function
3 =
Fault, coast
The motor stall protection protects the motor from short time overload
situations such as one caused by a stalled shaft. The reaction time of the
stall protection must be set shorter than that of motor thermal protection.
The stall state is defined with two parameters, P12.11 (Stall current) and
P12.13 (Stall frequency limit). If the current is higher than the set limit and
the output frequency is lower than the set limit the stall state is true. There
is actually no real indication of the shaft rotation. Stall protection is a type
of over current protection.
Under load protection
0 =
No action
1 =
Alarm
2 =
Fault, stop function
3 =
Fault, coast „Stop function" on page 119
The purpose of the motor underload protection is to ensure that there is
load on the motor when the drive is running. If the motor loses its load there
might be a problem in the process, e.g. a broken belt or a dry pump.
Motor underload protection can be adjusted by setting the underload curve
with parameters P12.14 (Underload protection: Field weakening area load)
and P12.15 (Underload protection: Zero frequency load), see the figure be-
low. The underload curve is a squared curve set between the zero frequency
and the field weakening point. The protection is not active below 5 Hz (the
underload time counter is stopped).
Application manual HVAC232/402 | Document 27-652 | Issue ENG06 | 2019-08-07
The torque values for setting the underload curve are set in percentage
which refers to the nominal torque of the motor. The motor's name plate
P12)
data, parameter motor nominal current and the drive's nominal current IL
are used to find the scaling ratio for the internal torque value. If other than
nominal motor is used with the drive, the accuracy of the torque calculation
decreases.
The default parameter value of the underload protection time limit is 20
seconds, which is the maximum time allowed for an underload state to exist
before causing a trip according to this parameter.
Torque
Underload curve at
field weakening point,
P12.14 (default) = 50%
Underload curve at
frequency zero load,
P12.15
(default) = 10%
5 Hz
Fig. 59. Underload protection
Underload area
f
Field weakening
point , P1.10
122

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