Table of Contents
Advertisement
Basic function principles
3.2
Chopper operation
Instead of a DC motor, you can connect a brake resistor (chopper) to a channel of the KL2532/KL2552 and
activate brake resistor mode for this channel (see KS2000 [} 42] or registers R33.0 - R33.3 [} 57]).
The motor must actively brake for positioning tasks. The mechanical energy is thereby converted back into
electrical energy. Small amounts of energy can be absorbed by a capacitor in the KL2532/KL2552. Further
storage capacities, for example in the power supply, can also take up energy. The feedback leads in each
case to a voltage increase.
In order to avoid overvoltage, a brake resistor can be connected to the KL2532/KL2552 in order to dissipate
the excess energy in the form of heat. When the voltage reaches 110% of the rated voltage (register R36
[} 58] , e.g. 55 V for KL2552), the correctly set output stage sends a fast-pulsed current through the brake
resistor (see diagram).
Fig. 6: Current through the brake resistor
U
/U
CH
N
U
at U
= 50 V
CH
N
U
at U
= 24 V
CH
N
Dimensioning of the brake resistor
The brake resistor should be dimensioned such that it can withstand the expected heat development with-
out damage!
A brake resistance of 10 Ω is recommended for KL2552, which results in a pulse current of approx. 5.5 A to
6.5 A. The maximum expected continuous power is 125 W. However, the value typically lies significantly
below that.
Load estimation (for KL2552)
P
= I
² x R
N
N
P
= (5A)² x 10 Ω
N
P
= 250 W
N
A maximum duty cycle of 50 % is possible. This results in a maximum continuous power of 125 W.
18
20%
40%
60%
10 V
20 V
30 V
4,8 V
9,6 V
14,4 V
Version: 3.2.0
80%
100%
40 V
50 V
19,2 V
24 V
NOTE
110%
130%
160%
55 V
65 V
80 V
25,2 V
31,2 V
38,4 V
KL2532/KS2532, KL2552/KS2552
Advertisement
Chapters
Table of Contents
