Baumuller b maXX BM5800 - Page 718

Monitoring
Parameter manual b maXX BM5800
Document No.: 5.16029.03 Baumüller Nürnberg GmbH
718
of 814
3.11
Initialization of the PT
1
element
If a temperature sensor is existing the motor temperature acquisition can be activated in
the "Acquisition system"
Z128.2–. The motor temperature actual value Z128.3– is
smoothed with the smoothing time constant 1 s.
If the acquisition of the motor temperature is active in the motor-I
2
t-time constant
Z107.28– = 0 or in the "NOT READY TO START" status the PT
1
element is set to the
motor temperature actual value or is initialized. Thereby, 40°C accord to 0% and approx-
imately (for easier use) 155°C 100%. For this reason the error number 205 "Motor I2t-
overload" can occur in spite of a low current or when switching on. If the motor tempera
-
ture acquisition is not existent or is not activated then the PT
1
element is initialized to 0%.
Standard solution and extended options
Within the total motor speed range the nominal current value is used as reference to cal-
culate the l
2
t actual value. Refer to chapter ZSpeed variable l
2
t overload monitoring– on
page 720 for implementations of a speed-dependent l
2
t monitoring.
By default, the apparent current of the motor is monitored. However, at low speeds the 3
phases are unequally loaded. Refer to chapter
ZMonitoring of the single phases– on
page 724 for information about monitoring each phase separately.
Example
In the following function example (refer to ZFig. 188– on page 720) a calculation of the
l
2
t actual value is introduced with consideration to the single warning /error thresholds by
using the standard solution (rated current of the total speed range).
NOTE!
If there is no motor temperature sensor available or activated then after an interrup-
tion and restarting of the l
2
t model again it cannot recognize a warm motor. In this
case the l
2
t model assumes a cold motor if it is started.
Power unit: b maXX
®
BM 5xxx I
limit
= 8 A
eff
Motor: DS 56 L - 3000 I
Motor
= 5,1 A
eff
Motor I
2
t time constant T
t
= 10 min = 600 s
Power unit S1 maximum current I
limit
Z175.8– 8 A
Motor nominal current I
N
Z107.9– 5,1 A
Motor I
2
t warning threshold Z6.39– 80% (Warning threshold)
I
2
t-Motor monitoring mode Z6.43– 0
Motor I
2
t -time constant T
t
Z107.28– 600 s
Total current actual value I'
act
Z6.30– A jump from 0 to 100% l
limit
of
the power unit