Enabling Of The Internal Braking (Enable Bu); Braking Unit Protection (Bu Protection); Figure 1.3.2.8.1: Braking Unit Function - GE AV-300i User Manual

1.3.2.8 Enabling of the Internal Braking (ENABLE BU)

1.3.2.8.1 Braking Unit Protection (BU Protection)

It controls the I 2 t Braking Unit protection function.
When the protection becomes active, it is possible to generate an alarm condition.
According to the different cases it is possible to use the device internal IGBT (Internal-External).
Overload factor = overload Power/ rated Power
Example:
DB resistance
Resistor continuos Amp rating = 15A
Rated for 5 X Amps for 15 secs
Resistor short time overload rating = 5 time quarter minute (5 time continuous amps for 15 secs)
Set parameters:
Bu resistance
Bu res cont pwr
Bu res OL time
Bu res OL factor
STARTUP
Startup config
BU protection
BU control
BU resistance
BU res cont pwr
BU res OL time
BU res OL factor
Ch.1
38
BU Control
T
BU resistance
External
Resistor
BU res cont pwr

Figure 1.3.2.8.1: Braking Unit Function

50 Ω
=
2
= 50 I * R
2
= 11.25 kW (15 * 50)
= 15 secs
= 25 (power = 12 R, 5 times overload current squared = 25)
—————— Function Description ——————
GEH-6641E
External
resistor
I 2 t
logic
BU res OL factor
BU res OL time
BU disable
BU
ALARM
Drive alarm