Toshiba – Toshiba Adjustable Speed Drive H3 User Manual
Page 85
TOSHIBA
9 - 16
Parameter Explanations (cont'd)
DYNAMIC BRAKING
(Feature not available in H3 drives above 30 horsepower)
When a motor is mechanically forced to spin faster than the output frequency of the drive, the
motor acts as a generator. This regenerated energy forces current to flow into the drive's DC
bus. The bus capacitors will absorb some of the regenerative energy by charging and raising the
DC bus voltage. At high bus voltages, the drive can be programmed to fire the IGBT7 dynamic
braking transistor. This prevents a common drive fault,
DC BUS OVERVOLTAGE
. The dynamic
braking resistor, attached by the user to the "PA" and "PB" terminals, dissipates the bus energy
as heat when the IGBT7 fires. Two resistor values are of concern: resistance (ohms) and power
(watts). Insufficient resistance may lead to IGBT7 damage; too low of a wattage may result in
braking resistor damage from overheating.
HEAVY DUTY RESISTORS
LIGHT DUTY RESISTORS
WATTS: 300 watts per drive HP
WATTS: 60 watts per drive HP
H3 H.D.
H3
H.D.
H3
L.D.
H3
L.D.
Model Ohms Model Ohms
Model Ohms Model Ohms
2035
35
4055
108
2035
150
4055
360
2055
28
4080
65
2055
90
4080
240
2080
20
4110
60
2080
61
4110
180
2110
12
4160
38
2110
45
4160
120
2160
7.0
4220
30
2160
30
4220
90
2220
6.0
4270
22
2220
23
4270
70
2270
5.0
4330
20
2270
18
4330
61
2330
4.0
2330
15
Contact your Toshiba distributor for dynamic braking resistor part numbers and information.
Item 145,
OVERVOLTAGE STALL PROTECTION
- This function is turned on as a default setting.
Overvoltage stall protection causes the drive to automatically extend the decel time when the DC bus
voltage increases due to regeneration. The value stored in
DECELERATION TIME #1
/
DECELERATION
TIME #2
is not changed. The drive may still trip on overvoltage if the decel time is very small.
Specifications
Precautions
Wiring
Jumpers
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Parameters
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