Nidec Digitax HD M75 Series, Инструкция по установке и техническое руководство

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Digitax HD M75X Series Installation and Technical Guide
59
Issue Number: 5
For high-inertia loads or under continuous braking, the continuous power dissipated in the braking resistor may be as high as the power rating of the
drive. The total energy dissipated in the braking resistor is dependent on the amount of energy to be extracted from the load.
The instantaneous power rating refers to the short-term maximum power dissipated during the on intervals of the pulse width modulated braking
control cycle. The braking resistor must be able to withstand this dissipation for short intervals (milliseconds). Higher resistance values require
proportionately lower instantaneous power ratings.
In most applications, braking occurs only occasionally. This allows the continuous power rating of the braking resistor to be much lower than the
power rating of the drive. It is therefore essential that the instantaneous power rating and energy rating of the braking resistor are sufficient for the
most extreme braking duty that is likely to be encountered. Optimization of the braking resistor requires careful consideration of the braking duty.
Select a value of resistance for the braking resistor that is not less than the specified minimum resistance. Larger resistance values may give a cost
saving. Braking capability will then be reduced, which could cause the drive to trip during braking if the value chosen is too large.
The following external brake resistors are available from the supplier of the drive for all frame sizes.
Table 4-12 External brake resistors (40 °C ambient) for all frame sizes
The thermal switch should be integrated in the control circuit by the user.
Pr
10.030 , Pr 10.031 and Pr 10.061 should be set as per information provided in Table 4-11. Refer to description of Pr 10.030 , Pr 10.031 and
Pr 10.061 in section 4.8.3 Braking resistor software overload protection on page 60 for more information.
Thermal protection circuit for the braking resistor
The thermal protection circuit must disconnect the AC supply from the drive if the resistor becomes overloaded due to a fault. Figure 4-8 shows a
typical circuit arrangement.
Figure 4-8 Typical protection circuit for a braking resistor
See Figure 4-1 on page 48 for the location of the +DC and braking resistor connections.
Part
number
Part
description
Ohmic
value
Pr 10.061
Continuous
power
rating
Pr 10.030
Max instant
power rating
ton = 1 ms
Pulse power
1/120 s
(ED 0.8 %)
Pulse power
5/120 s
(ED 4.2 %)
Pulse power
10/120 s
(ED 8.3 %)
Pulse power
40/120 s
(ED 33 %)
Time
constant
Pr 10.031
1220-2201
DBR.
100 W,
20R, 130 x
68, TS
20 Ω 100 W 2.0 MW 2300 W 1000 W 650 W 250 W 2
1220-2401
DBR.
100 W,
40R, 130 x
68, TS
40 Ω 100 W 1.6 MW 1900 W 900 W 610 W 240 W 2
1220-2801
DBR.
100 W,
80R, 130 x
68, TS
80 Ω 100 W 1.25 MW 1500 W 775 W 570 W 230 W 2
Optional
EMC
filter
Stop
Start /
Reset
Thermal
protection
device
Braking resistor
Drive
Main contactor
power supply
+DC
BR