Vacon Plc
Phone: +358-201 2121
Fax:+358-201 212 205
Service: +358-40-8371 150
E-mail: [email protected]
E-mail: [email protected]
Vacon
Page 41
Pump control with autochange
f
I
Par. 7
.
11
Par. 7
.
13
UMCH7_11
Stall area
Figure 6-21 Setting the stall
characteristics.
7. 12
Stall time
The time can be set between 2.0—120 s.
This is the maximum allowed time for a stall stage. There is an internal up/down
counter to count the stall time. Refer to the figure 6-22.
If the stall time counter value goes above this limit the protection will cause a trip
(refer to the parameter 7
.
10).
Par. 7
.
12
UMCH7_12
Trip area
Time
Stall time counter
Stall
No stall
Trip/warning
par. 7
.
10
Motor underload protection can be adjusted by set-
ting the underload curve with parameters
7
.
15 and 7
.
16. The underload curve is a squared
curve set between zero frequency and the field
weakening point. The protection is not active below
5Hz (the underload counter value is stopped). Refer
to the figure 6-23.
The torque values for setting the underload curve
are set in percentage which refer to the nominal
7. 11
Stall current limit
The current can be set between
0.0—200% x I
nMotor
.
In the stall stage the current has to
be
above this limit. Refer to the
figure 6-21. The value is set as a
percentage of the motor's name
plate data, parameter 1. 13,
motor's nominal current. If
parameter 1. 13 is adjusted, this
parameter is automatically
restored to the default value.
7. 13
Maximum stall frequency
The frequency can be set between
1—f
max
(par. 1
.
2).
In the stall state, the ouput
frequency has to be smaller than
this limit. Refer to the figure 6-21.
Figure 6-22 Counting the stall time.
Parameters 7. 14— 7. 17, Underload protection
General
The purpose of motor underload protection is to ensure that there is load on the motor whilst
the drive is running. If the motor looses its load there might be a problem in the process, e.g. a
broken belt or dry pump.
