ABB ACS 800 Series User guide

ACS800
Application Guide
ACS800 Single Drive Common DC Configurations

ACS800 Single Drive Common DC Configurations
Application Guide
3AFE64786555 REV E
EN
EFFECTIVE: 03.12.2004
2004 ABB Oy. All Rights Reserved.

5
Table of contents
Introduction
Possible main supply connections
Step by step guide
Design
Power limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Allowed braking power and need for a brake resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Calculation of the allowed braking power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Internal brake chopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
External brake chopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Contactors, DC bus and brake circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Wiring
Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Powering the AC fans in R7 and R8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Brake resistor circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Connecting the contactor of the resistor circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Phase loss guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
READY signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Wiring the READY signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Start-up
Appendix A Charging circuit capacity
Frame sizes R...R4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Frame sizes R5...R8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Appendix B Powering the AC fans of R7 and R8

6

Introduction
7
Introduction
Connecting the DC buses of frequency converters together results in energy savings
and in some cases simplifies the connection to the main supply. With common DC
the braking energy of one converter can be used for the other converters and
motors.
Unequal current distribution and different charging methods cause difficulties to
common DC systems:
• Unequal current distribution is influenced by input cables, AC or DC chokes and
input bridges’ forward characteristics. If the voltage reduction over the supply
components mentioned is not the same with all converters, more current will flow
through the converter which has a lower voltage reduction. Factors which
influence the current distribution include temperature, tolerances of components
and in DC choke cases the input cable’s cross-sectional area and length.
• Charging methods vary depending on the converter size. Because of this in some
installations, the supplies of the frame sizes R2-R4 should be disconnected when
they are connected parallel with frame sizes R5-R8.
Note: The drive compliance with the EMC Directive on low voltage networks is
specified in the appropriate Hardware Manual. However, please notice that different
common DC configurations have not been tested according to the EMC
requirements of conducted and radiated emissions.

Possible main supply connections
8
Possible main supply connections
Figure 1. Common DC connections. Cases a and b.
Figure 2. Common DC connections. Cases c, d1 and d2.
Cases b, c and d can be used when the total power taken from the main supply,
Pout.tot, is smaller than the drive power rating, Pcont.max, of the biggest converter.
+
-+ -+ -
R8 R7 R6
F8 F7 F6
M
3~
M
3~
M
3~
+
-+ -+ -
F8
R8 R8 R8
F8
M
3~
M
3~
M
3~
+
-+ -+ -
R6 R8 R7
F8
F6 F7
M
3~
M
3~
M
3~
+
-+ -+ -
R7 / R6 R7 R7 / R5
F7
M
3~
M
3~
M
3~

Possible main supply connections
9
Case a)
The most common set-up, where all converters are connected to the main supply.
When the charging circuits of the converters are different, this connection is not
always allowed. Table 1 shows when the connection cannot be used.
Case b)
Converters are identical and only one converter is connected directly to the main
supply.
Case c)
Converters are not identical and only the biggest converter is connected directly to
the main supply. The AC cables to the other converters are protected by
drive-specific fuses.
Case d1)
Converters are identical and only one converter is connected directly to the main
supply. The charging circuit of the connected converter is capable of charging the
whole DC bus.
Case d2)
Converters are not identical and only the biggest converter is connected to the main
supply. Charging circuit of the connected converter is capable of charging the whole
DC bus.
Note: If the charging circuit in case d1/d2 is not capable of charging the DC bus,
connection presented in case b/c must be used.
Note: With frame sizes R5...R8 the charging circuit in case d1/d2 might not be able
to withstand the three times larger charging energies. In this case the main supply
cable is wired to all of the input rectifiers as presented in case b/c.
Note: With ACS800-11 only connection presented in case d1/d2 is allowed.
Note: With ACS800-11 220 V units, the voltage drop over the charging resistor
during charging can generate a permanent undervoltage fault. Contact your local
ABB representative for help on designing the common DC configuration!
To determine whether it is possible to leave some converters unconnected to the
main supply see Appendix A Charging circuit capacity.

Step by step guide
10
Step by step guide
1) Select the converters and preselect the main supply connection. See Possible
main supply connections and Appendix A Charging circuit capacity.
2) Check from Table 1 that the connection is possible.
3) Check by using equation 1 that the load does not exceed the total power limit
Pout.tot of the system. See Power limit.
4) Select the fuses, cables and possible contactors for the DC side. See Fuses,
Cables and Contactors, DC bus and brake circuit.
5) Calculate the braking power and determine whether the braking cycle can be
performed and whether an internal or an external brake chopper is needed. See
Allowed braking power and need for a brake resistor.
6) If resistor braking is needed, select the internal or external brake chopper, the
resistor and the contactor. See Internal brake chopper, External brake chopper and
Contactors, DC bus and brake circuit.
7) Set up the common DC system according to the wiring instructions. See Wiring.
8) If the input terminals of frame sizes R7 and R8 are left unconnected, make sure
that the AC fans are powered separately. See Appendix B Powering the AC fans of
R7 and R8.
9) Set the common DC system related parameter values. See Start-up.

Design
11
Design
Power limit
Total output power limit of the common DC system can be calculated with
equation 1.
Pout.tot is the instantaneous power limit of the installation. P1cont.max is the lowest
and Pn.cont.max the highest drive power rating of the converters.
Only converters, which are connected to the main supply, are used for the power
limit calculations.
The power correction factor, k, for each combination can be found from Table 1.
When several converters are connected to the main supply, the least efficient power
correction factor is chosen from table 1, i.e. the smallest factor. See Example1 and
Example2.
Table 1 Power correction factors
Explanations of Table 1:
NO: The supply of the smaller converter MUST NOT be connected, because the
converters have different input chokes. Frame sizes R2...R3 have DC chokes and
frame sizes R4...R8 AC chokes.
C: If both converters are connected to the main supply, the DC links MUST be
connected together via contactor because the converters have different charging
circuits. In R2...R4 the charging resistors are in series with the DC capacitors and in
R5...R8 the charging resistor is in parallel with the input bridge. The DC contactors
are switched on after all of the DC links are charged and the converters are in the
READY state.
Note: The Pout.tot value is higher if the smallest converter is not connected to the
main supply.
ACS800
R2-R3 R4 R5-R6 R7-R8
R2-R3 k=0.5NONONO
R4 NO k=0.7 k=0.7 C k=0.7 C
R5-R6 NO k=0.7 C k=0.7 k=0.6
R7-R8 NO k=0.7 C k=0.6 k=0.7
Pout.tot P1cont.max kP
2cont.max
⋅kP
n.cont.max
⋅++=(equation 1)

Design
12
Example1
The DC buses of three converters ACS800-0004-5, 2.2 kW, R2; ACS800-0025-5,
18.5 kW, R3 and ACS800-0025-5, 18.5 kW, R3 are connected together. The input
terminals of the 2.2 kW converter are left unconnected. According to Table 1, k = 0.5
when two R3´s are connected to the main supply, therefore Pout.tot is
Example2
The DC buses of three converters ACS800-0050-5, 37 kW, R5; ACS800-0140-5,
110 kW, R6 and ACS800-0320-5, 250 kW, R8 are connected together. All three
converters are connected to the main supply. According to Table 1, k = 0.7 when R5
and R6 are connected to the main supply and k = 0.6 when R6 and R8 are
connected to the main supply. The worst case is chosen for the calculations, i.e.
k = 0.6, therefore Pout.tot is
Pout.tot 18.5kW 0.5 18.5kW⋅+ 27.75kW==
Pout.tot 37kW 0.6 110kW⋅0.6 250kW⋅+ + 253kW==

Design
13
Fuses
Use fuses listed in the appropriate drive Hardware Manual for input cable protection.
The recommendations for obligatory DC side semiconductor fuses, aR fuses, are
listed in Table 2.Use 690 VAC rated fuses for 230...500 V converters and 1250 VAC
rated fuses for 690 V converters. The aR fuses protect the converter against short
circuits in other converters. Because of the complicated fault current paths the
selectivity of the fuses cannot be guaranteed in all conditions.
aR fuses must be installed on both DC wires.
Table 2 Recommended DC side aR fuses.
ACS800-01/04/11
Frame size 230 V 400 V 500 V 690 V I / A
R2 0001-2, 0002-2, 0003-2 0003-3, 0004-3, 0005-3 0004-5, 0005-5, 0006-5 20
R2 0004-2 0006-3 0009-5 25
R2 0005-2 0009-3 0011-5 40
R3 0006-2, 0009-2 0011-3, 0016-3 0016-5, 0020-5 50
R3 0011-2 0020-3, 0023-3 0025-5 63
R4 0011-7 25
R4 0016-7 32
R4 0020-7 40
R4 0016-2, 0020-2 0025-3, 0030-3 0028-5, 0030-5, 0040-5 0025-7 63
R4 0035-3 0045-5 0040-7 80
R5 0025-2 0040-3 0050-5 0050-7, 0060-7 100
R5 0030-2 0050-3 0060-5, 0070-5 125
R5 0040-2 0060-3 160
R6 0070-7 125
R6 0100-7 160
R6 0120-7 200
R6 0050-2, 0060-2 0070-3, 0100-3 0100-5, 0120-5 315
R6 0070-2 0120-3, 0130-3 0140-5, 0150-5 400
R6 0140-7, 0170-7 350
ACS800-0x
Frame size 230 V 400 V 500 V 690 V I / A
R7 0080-2 0140-3 0170-5 0210-7, 0260-7 400
R7 0100-2 0170-3 0210-5 500
R7 0120-2 0210-3 0260-5 550
R8 0320-7, 0400-7 700
R8 0140-2, 0170-2 0260-3 0270-5, 0300-5, 0320-5 0440-7 800
R8 0490-7, 0550-7 900
R8 0210-2 0320-3 0400-5 0610-7 1000
R8 0230-2 0400-3 0440-5, 0490-5 1250
R8 0260-2, 0300-2 0440-3, 0490-3 0550-5, 0610-5 1600

Design
14
Cables
• Select the input power cables as described in the appropriate drive Hardware
Manual. The cross-sectional area of the DC cables must be the same as the
cross-sectional area of the AC side cables.
• If screened DC cables are used, ground the screen at the other end only.
• The lengths of the supply cables must not differ more than 15%. This applies
especially to converters equipped with DC chokes.
• Maximum length of the DC cables between two converters is 50 m.
• If the system consists of more than two converters, the DC links must be
connected in an external terminal box. Do not use the terminals of one of the
converters for this purpose.

Design
15
Allowed braking power and need for a brake resistor
1. For each drive check that the braking power does not exceed the allowed braking
power. See Calculation of the allowed braking power below.
2. For the common DC system check whether it needs to be equipped with an
additional brake chopper and resistor. This is the case if the total power of the
common DC system is negative at any point of the duty cycle [i.e. braking motor(s)
regenerate more power to DC link that can be consumed by other motors]. See the
figure below which shows the duty cycles of three drives and the sum, the common
DC duty cycle. A brake chopper and a resistor is needed to dissipate the surplus
braking energy (the shaded areas).
Common DC
duty cycle
Drive C
duty cycle
Drive B
duty cycle
Drive A
duty cycle
P
t
P
t
P
t
P
t

Design
16
Calculation of the allowed braking power
If drive is not connected to the main supply, ensure that the braking power meets
condition 1 below.
If drive is connected to the main supply, ensure the braking power meets condition 1
AND condition 2 below.
Condition 1
The drive braking power may not exceed the drive power rating.
Condition 2
The power flowing through the converter's DC bus terminals to the other drives may
not exceed the drive power rating. This might happen when drive brakes and takes
power from the main supply at the same time. The power rating of the terminals is
not exceeded when the following condition is valid, i.e. the sum of the drive input
power and the drive braking power has to be equal or smaller than the drive power
rating.
Pbr Pcont.max ≤
Pbr = braking power
Pcont.max = drive power rating
P1P2…PnPbr –+++
Pout.tot
---------------------------------------------------------Pcont.max
⋅Pbr Pcont.max ≤+
Pbr = braking power
Pcont.max = drive power rating
Pout.tot = power limit of the common DC system
P1...n = simultaneous loads of the other converters

Design
17
Example 3
The DC buses of three converters ACS800-0140-5, 110 kW, R6; ACS800-0140-5,
110 kW, R6, and ACS800-0070-5, 55 kW, R5 are connected together. Only one
110 kW converter is connected to the main supply. The duty cycle is shown in the
table below.
Allowed braking powers
R6 connected to main supply:
Condition 1: 70 kW < 110 kW OK
Condition 2:
Pout.tot of the system is 110 kW.
R6 not connected to main supply:
Condition 1: 30 kW < 110 kW OK
R5 not connected to main supply:
Condition 1: 30 kW <55 kW OK
Need for a brake resistor
The total power of the common DC system is negative during phase interval t3...t4,
therefore a brake chopper and a brake resistor are needed.
Phase Converter powers (kW) Common DC
duty cycle (kW)
R6 (AC supplied) R6 R5
0…t1 110 -30 30 110
t1…t2 60 0 30 90
t2…t3 -70 70 30 30
t3...t4 -50 70 -30 -10
t4…t5 0 -30 30 0
70kW 70kW–30kW+
110kW
---------------------------------------------------------110kW⋅70kW+ 100kW 110kW≤=
70kW 50kW–()30–()kW+
110kW
--------------------------------------------------------------------110kW⋅50kW+ 40kW 110kW≤=

Design
18
Internal brake chopper
• Only one internal brake chopper is allowed to be active.
• If an internal chopper is used, it must be in the biggest converter.
• The maximum braking power of the brake chopper or the inverter must not be
exceeded.
• A contactor must be used in the resistor circuit for protection against brake
chopper faults and against the overtemperature of the resistor.
External brake chopper
• An external brake chopper can be used but not at the same time with an internal
brake chopper.
• The external chopper must be installed close, < 5 m, to the biggest braking
converter.
• The external chopper can be selected according to the braking power demand.
For more information, see the appropriate drive Hardware Manual.
• A contactor must be used for protection against brake chopper faults.
Contactors, DC bus and brake circuit
If converters with different charging circuits are connected directly to the main
supply, the DC links must be connected together via contactors. See Table 1.
With an external or an internal brake chopper a contactor must be used for
protection against brake chopper faults.
•Contactors must be capable of cutting off the DC current. The maximum
operational voltage over the contactor is the DC voltage during the braking, i.e.
1.21 · 1.35 · U1.
• DC current rating for the DC contactor can be calculated by using equation 4.
Pcont.max is the drive power rating of the biggest converter and U1is the supply
voltage of the converter.
IDC
PDC
UDC
-----------
=
PDC Pcont.max ≈(equation 4)
UDC 1.35 U1 ⋅=

Design
19
Peak current through the contactor in brake resistor circuit can be calculated with
equation 5.
The rms current during the braking can be calculated with equation 6.
Rbrake is the brake resistor‘s resistance. Pbr is the applied braking power.
I
ˆ1.21 UDC
⋅
Rbrake
-------------------------
=(equation 5)
Irms
Pbr
Rbrake
-------------=(equation 6)

Wiring
20
Wiring
Supply
Use the same supply connection point. All converters must be fed from the same
transformer. The supply impedance is an important parameter, which influences the
current distribution. All converters must have equal supply impedance.
Powering the AC fans in R7 and R8
See Appendix B Powering the AC fans of R7 and R8 for more information.
Brake resistor circuit
Figure 3 presents an example of a three converter system. Both internal and
external brake choppers are shown.
Only one brake chopper is allowed to be used.
When an internal chopper is used, contactor K1 disconnects both poles of the brake
resistor when a fault is detected. An auxiliary contactor of the contactor K1 is used to
trip the drive on a START INHIBIT fault when the brake resistor overheats.
When an external chopper is used, contactor K3 disconnects both poles of the brake
resistor when a fault is detected. When the brake resistor is disconnected the whole
system will trip on a OVERVOLTAGE fault.
Connecting the contactor of the resistor circuit
• Wire an output relay of the RMIO board to control the contactor. The default value
is that the contactor is closed during normal operation and when the power is off.
• Set the output relay to open when drive trips on a FAULT or BC SHORT CIRCUIT.
See appropriate drive parameter from parameter group 14.
Warning! Application macro change resets the settings. Restore the settings to
correct values after the macro change.