GE Nail Gun 6KBU300 Braking Unit User Manual

INSTRUCTIONS  
GE Industrial Control Systems  
6KBU300  
Braking Unit  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300 Braking Unit  
Instruction Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
This book replaces the Instruction Book GEI-100350A Rev. 1.0 (9/97)  
All rights reserved  
These instructions do not purport to cover all details or variations in equipment, nor to provide every possible contin-  
gency to be met during installation, operation, and maintenance. If further information is desired or if particular prob-  
lems arise that are not covered sufficiently for the purchaser’s purpose, the matter should be referred to GE Industrial  
Control Systems.  
This document contains proprietary information of General Electric Company, USA and is furnished to its customer  
solely to assist that customer in the installation, testing, operation, and/or maintenance of the equipment described.  
This document shall not be reproduced in whole or in part nor shall its contents be disclosed to any third party without  
the written approval of GE Industrial Control Systems.  
© 1998 by General Electric Company, USA. All rights reserved.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
CONTENTS  
1. GENERAL ———————————————————————————— 1  
2. MAINS CHARACTERISTIC —————————————————————— 1  
3. TECHNICAL DATA ————————————————————————— 1  
3.1. DIMENSIONS AND WEIGHTS ———————————————————————— 1  
3.2. HARDWARE SPECIFICATIONS ———————————————————————— 3  
3.2.1. Power required —————————————————————————— 3  
3.2.2. Internal fuses —————————————————————————— 3  
3.2.3. Signalling LEDs —————————————————————————— 3  
3.2.4. Terminal strip —————————————————————————— 3  
3.2.5. Dip Switches description —————————————————————— 5  
3.3. SELECTION OF THE INTERVENTION THRESHOLD ————————————————— 5  
3.4. PARALLEL CONNECTION OF THE UNIT———————————————————— 5  
3.5. OVERTEMPERATURE ALARM. ———————————————————————— 7  
3.6. USE OF DC LINK DISCHARGE FUNCTION ———————————————————— 8  
4. DIMENSIONING OF THE BRAKING UNIT AND CORRESPONDING RESISTANCE 1  
4.1. SIMPLIFIED DIMENSIONING OF THE RESISTANCE ———————————————— 4  
5. MINIMUM VALUE OF THE RESISTANCES THAT CAN BE UTILIZED ———— 1  
6. STANDARD BRAKING RESISTANCES ————————————————— 1  
7. EXTERNAL PANEL MOUNTED DC FUSE ———————————————— 1  
8. BLOCKS DIAGRAM———————————————————————— 1  
I
—————— CONTENTS ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
1. GENERAL  
The braking unit 6KBU300 is basically composed by a static switch (IGBT) controlling the voltage of the intermediate  
circuit of the inverter (DC Link), dissipating the energy generated by the motor (and correspondent load) connected  
to the inverter while deceleration steps, by turning on and channeling excess energy through a resistor.  
With this technique it is possible to obtain faster decelerations, operate overhauling loads avoid the tripping of the  
“Overvoltage” protection of the inverter, which could be caused by a sudden increasing of the DC Link voltage.  
Through a parallel connection of the units between terminals C and D, and a cascade connection of the braking  
command (master/slave configuration), it is possible to parell four-units in connection.  
A thermal protection contact input of the braking resistor with latched alarm is provided.  
The latched alarm can be reset, once the alarm condition has been eliminated, by means of the button present on  
the unit, or by a remote command, or switching off and on again the braking unit.  
A quick discharge of the inverter’s intermediated circuit (DC Link) can be commanded.  
This command must be directly interblocked with the contactors that supply the energy to the inverters  
and suitably interlocked to not discharge while the drive is enabled.  
1
1
—————— GENERAL ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
2. MAINS CHARACTERISTICS  
-
-
-
-
-
-
Protection IP20  
Max. working temperature 40°C (104°F) ambient (max 50°C (122°F) with a 20% of derating)  
Costant switching on time (max. time ON) 3 minutes  
Max.duty cycle admitted 50%  
Supply of the circuit obtained by the DC Link  
Possibility of parallel connection up to 3 units managed by a “MASTER” unit (4 slave units managed by a  
drive set as master)  
-
-
-
-
-
-
-
-
DC Bus threshold set by dip switches  
Signaling of the +24V supply presence (Green diode led +24V)  
Signaling of the Brake unit activity (Yellow diode led BR)  
Signaling of alarm condition AL (Red diode led AL)  
Signaling of OK condition (Green diode led OK)  
OK relay dry contacts available for alarm sequences  
Input to connect a resistor mounted klixon contact  
Possibility of quick discharge of the DC Link.  
1
2
—————— MAINS CHARACTERISTIC ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
3. TECHNICAL DATA  
Model  
Dissipated power @ Full load  
Peak current  
Average current  
20 A  
6KBU300-20  
6KBU300-50  
6KBU300-85  
130 W  
300 W  
400 W  
50 A  
100 A  
170 A  
50 A  
85 A  
bu0005  
WARNING!  
The electronic circuit of the braking unit is directly connected to the DC Link whose voltage  
value can reach up to 770Vdc.  
When the cover of the drive is not removed, the live parts are not accessible (IP 20)  
3.1. DIMENSIONS AND WEIGHTS  
BR CR C D  
b1  
b
a1  
c
a
Model  
a
b
c
a1  
b1  
lbs/Kg  
in/mm in/mm  
in/mm  
in/mm  
in/mm  
6KBU300-20  
6KBU300-50  
6KBU300-85  
5.7/144 12.6/320 8.27/210  
5.7/144 12.6/320 8.27/210  
5.7/144 12.6/320 11.1/280  
2.8/71 12.1/307  
2.8/71 12.1/307  
2.8/71 12.1/307  
M 6  
M 6  
M 6  
11.5/5.2  
12.5/5.7  
15/6.8  
bu0045  
1
3
—————— TECHNICAL DATA ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
+24V  
BU-300  
F2  
75  
76  
75  
NC  
76  
NC  
NC  
S3 RESET  
1
2
+24V  
0V24  
TIM  
3
4
RESET  
MCMD  
0V24(MCMD)  
SIN  
5
6
7
8
SIN  
SOUT  
SOUT  
9
10  
NC  
400V  
640V  
680V  
745V  
S1  
1. DC Link input power must be removed  
and fully discharged before removing  
cover, or performing maintenance or  
inspection  
DCHG  
ON  
2. Do not perform voltage test with meggar  
on regulation card terminals  
CAUTION  
SLAVE  
MASTER  
MASTER  
BR  
GE Drive  
OK  
AL  
Front view  
2
3
—————— TECHNICAL DATA —————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
3.2. HARDWARE SPECIFICATIONS  
3.2.1. Power required  
The supply of the braking unit is directly obtained by the DC Link and the maximum consumption is 15W.  
3.2.2. Internal fuses  
Denomination  
Protection for  
Switching input supply  
Fuses  
F1  
F2  
4A 500V slow 6 x 32 mm  
315mA 250V slow 5 x 20 mm  
+24V supply (terminals 1 and 2)  
Master output command (terminals 5 and 6)  
Supply of the internal fan (+24V)  
F3  
1A 250V slow 5 x 20 mm  
bu0015  
The fuse F2 for the +24V supply (terminals 1 and 2) and Master output command (terminals 5 and 6) is mounted  
on the front panel.  
Replacement vendor sources:  
Fuse 1  
Fuse 2  
- Omega (Europe) GF632240  
- Omega (Europe) ST520131  
- Littlefuse 218315  
Fuse 3  
- Omega (Europe) ST520210  
- Littlefuse 218001  
3.2.3. Signalling LEDs  
Denomination  
Colour  
green  
yellow  
yellow  
green  
red  
Function  
24 V  
MASTER  
BR  
It shows presence of the power supply  
The braking unit is set as master  
The braking unit is active (braking)  
OK relay status (closed = OK)  
It shows the alarm condition  
OK  
AL  
bu0020  
3.2.4. Terminal strip  
The power terminal strip is composed by the following terminals:  
Terminals  
C
Function  
I/Q  
Volt. max.  
Curr. max.  
Connection to the intermediate circuit of the  
inverter  
I
770Vdc  
I peak  
Connection to the intermediate circuit of the  
inverter  
D
I
770Vdc  
I peak  
CR  
BR  
PE  
Connection to the braking resistor  
Connection to the braking resistor  
Ground connection  
Q
Q
745V dc  
745V dc  
I peak  
I peak  
bu0025  
3
3
—————— TECHNICAL DATA ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
Regulation board terminal strips:  
Terminals  
Name  
+24V  
Function  
I/Q  
Volt. max.  
Curr. max.  
200mA  
1
2
Supply for commands TIM-RESET  
0V potential of the +24V supply  
Q
24V  
0V 24V  
Connection for the thermal contact of  
resistor protection  
3
4
TIM  
I
15...30V  
15...30V  
3.2...6.4 mA  
3.2...6.4 mA  
RESET Remote Reset of alarm condition  
MCMD Slave unit command (Master output)  
I
5
6
Q
24V ± 5%  
30 mA  
0V 24V  
SIN  
0V potential of MCMD command  
Slave unit input command  
7
I
8...30V  
8...30V  
8...30V  
8...30V  
250Vca  
250Vca  
16 mA  
16 mA  
16 mA  
16 mA  
1 A  
8
SIN  
Slave unit input command  
I
9
SOUT  
SOUT  
OK  
Cascade connection of Slave units  
Cascade connection of Slave units  
OK relay dry contact (closed = OK)  
OK relay dry contact (closed = OK)  
Q
Q
Q
Q
10  
75  
76  
OK  
1 A  
bu0030  
Maximum cable sizes for power terminals C,D,CR,BR  
Braking Unit type  
Maximum Permissible Cable Cross-Section  
[mm2]  
AWG  
flexible  
10  
multi-core  
6KBU300-20  
6KBU300-50  
6KBU300-85  
10  
16  
35  
12  
10  
2
16  
35  
bu0031  
Maximum cable sizes of the regulation section terminals  
Terminals  
1 ... 76  
Maximum Permissible Cable Cross-Section  
[mm2]  
AWG  
22 ... 16  
flexible  
multi-core  
0.35 ... 1.5  
0.35 ... 1.5  
bu0032  
4
3
—————— TECHNICAL DATA —————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
3.2.5. Dip Switches description  
Denomination  
Function  
S1-1  
Enabling of the function for quick discharge of the DC link  
Standard = OFF  
S1-2 ... S1-5  
Selection of intervention threshold of the braking unit  
Braking threshold  
400V dc  
S1-2  
OFF  
OFF  
OFF  
ON  
S1-3  
OFF  
OFF  
ON  
S1-4  
OFF  
ON  
S1-5  
ON  
640V dc  
OFF  
OFF  
OFF  
680V dc  
OFF  
OFF  
745V dc  
OFF  
S1-6  
S2  
Not used  
MASTER = Selection of braking unit function as Master (standard)  
SLAVE = Selection of braking unit as Slave  
S3  
Button Reset of alarm condition  
bu0035  
3.3. SELECTION OF THE INTERVENTION THRESHOLD  
The DC threshold of the braking unit must be set accordingly to the supply voltage value of the connected  
inverter, setting the switches as described in the following table.  
NOTE:  
It is possible to select only one braking threshold at a time.  
Voltage  
Braking threshold  
[VBR  
Position of the switches  
supply  
230Vac  
400Vac  
460Vac  
]
S1-2  
OFF  
OFF  
ON  
S1-3  
OFF  
ON  
S1-4  
OFF  
OFF  
OFF  
S1-5  
ON  
400Vdc  
680Vdc  
745Vdc  
OFF  
OFF  
OFF  
bu0010  
3.4. PARALLEL CONNECTION OF THE UNIT  
There is the possibility to connect up to four braking units in parallel. For this purpose, terminals C and D must be  
parallel connected and one of the units must be set as Master function, while the others as Slave (through switch  
S2).  
Only the Master needs to be selected for the desired intervention threshold (through switches S1-2...S1-5).  
Connect the braking units as showed in the picture, paying particular attention to the correspondance of the  
terminals connection C and D. For the cascade’s command connections (terminals 5 ... 10) correspondence of  
terminals polarity is not requested, but it is advisable to use twisted cables.  
5
3
—————— TECHNICAL DATA ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
In this configuration, when the Master unit reaches the set intervention threshold, it manages also the intervention  
of the first Slave unit by means of the command MCMD (output terminals 5 and 6), which is cascade connected  
to the input SIN of it (terminals 7 and 8). At its turne, the second Slave will be enabled by the command SOUT  
(output terminals 9 and 10) of the first Slave.  
In case of inverters provided with internal command for external brake units, all the 6KBU300 units must be set  
as Slave. The terminals MCMD and 0V24 of the drive have to be connected to the terminals 7 and 8 (SIN) of the  
first 6KBU300, which will be of course connected to the next through its own terminals 9 and 10 (SOUT), as  
described in the next page.  
NOTE:  
When a very close mounting of several braking units is needed, it is necessary to keep among  
them a minimum distance of 5 centimeters (2 inches).  
NOTE:  
WRONG CONNECTIONS OF THE POWER PART CAN CAUSE THE DESTRUCTION  
OF THE UNIT AND/OR OF THE CONNECTED INVERTERS IF DC LINK FUSES  
ARE NOT SUPPLIED !!  
AC Input  
from C and D of inverter  
*
*
INVERTER  
MASTER  
CR  
BR  
C
C
D
D
MASTER  
9
10  
5
7
6
8
7
8
C
CR  
BR  
*
*
*
*
C
CR  
BR  
D
SLAVE  
D
SLAVE  
10  
9
7
10  
9
7
8
8
CR  
BR  
C
*
*
*
*
CR  
BR  
C
D
SLAVE  
D
SLAVE  
9
10  
9
10  
* If supplied (see section 7)  
** MCMD terminal is available only for Drives  
having "Product configuration C1" or higher  
Example of three units connected in parallel through 6KBU300 or inverter Master  
6
3
—————— TECHNICAL DATA —————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
The max. lenght of the connections between braking units and inverters must not exceed two meters, (the  
twisted connection with the appropriate wire section, is always supplied together with the braking unit).  
For the parallel connection of braking units, the user must always use a twisted cable; the units should however  
be mounted side by side and the connections between terminals C and D should be kept as short as possible.  
The power fuses of the correspondent inverters must be super fast.  
3.5. OVERTEMPERATURE ALARM.  
When the braking resistor reaches too high temperature, there is the possibility to trip out the braking unit. This  
happen by means of the thermal relay (Klixon), and connecting its contact (normally closed) between the output  
+24V (terminal 1) and the input protection TIM (terminal 3).  
The contact of the thermal relay can be also externally supplied with a voltage between 15 and 30V whose 0V  
potential must be connected to the 0V24V (terminal 2).  
When there is the intervention of the thermal relay (opening of the contact) the braking unit is immediately tripped  
, the red led AL lights on and the OK relay contact opens (terminals 75 76).  
When an Overtemperature alarm occurs due to an overheating of the power module’s heatsink (opening of the  
relative thermal relay), a BU trip occurs.  
Once the alarm has been eliminated, it is possible to reset the braking unit using one of these modalities:  
-
-
-
through button S3  
through remote command inserted on the terminal 4  
removing BU from DC BUS  
The diagrams in the following pictures show a typical connection for protection with an external contact for the  
alarm reset.  
To the inverter  
To the inverter  
5
6
5
6
CR  
BR  
C
R
CR  
BR  
C
R
D
15…30Vdc  
0V  
D
3
2
4
3
1
PE  
7
PE  
4
10  
8
9
Alarm reset  
10  
9
7
8
Alarm reset  
Using the internal power supply of the braking unit  
Using external power supply from the unit  
7
3
—————— TECHNICAL DATA ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
3.6. USE OF DC LINK DISCHARGE FUNCTION  
The braking unit can be used for discharging of DC Link with high capacitive value (e.g. in systems where the  
DC Link is parallel connected) by a dipswitch setting.  
In order set the switch S1-1 in position ON and bridge terminals 9 and 10.  
In this condition the discharge of DC Link is obtained up to a value equal or lower than 60Vdc, applying an  
external voltage between 10 and 30Vdc to the terminals 7 and 8 (SIN) or using the internal voltage present at the  
terminals 1 and 2.  
In order to avoid damages to the braking resistor, the user must pay particular attention to the inser-  
tion sequence of this command. The signal must be supplied to the braking unit through an interblocked  
contact with the contactors that supply the inverters.  
8
3
—————— TECHNICAL DATA —————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
4. DIMENSIONING OF THE BRAKING UNIT AND  
CORRESPONDING RESISTOR  
What below indicated should be meant in general, because point 6 reports a list of the normalised resistor which  
must be used with the braking units of the series 6KBU300-.. for the supposed conditions.  
Taking into account that:  
PPBR [W]  
PNBR [W]  
EBR [J]  
Peak power while braking  
Rated power of the resistor  
Braking energy  
VBR [V]  
Braking voltage threshold  
Peak braking current  
IPBR [A]  
IAVBR [A]  
IPBU [A]  
Average braking current  
Peak current of the braking unit  
Initial and final speed  
n1, n2 [RPM]  
tBR, T [S]  
JTOT [Kg* m2]  
Braking time and cycle time  
Total moment of inertia (referred to the motor shaft )  
We will have:  
n1-n2  
tBR  
2Π  
60  
*
PPBR = JTOT * n1 *  
f001  
JTOT  
2
2Π  
60  
)2*(n12-n22)  
EBR  
=
*(  
PPBR  
VBR  
IPBR  
=
f003  
VBR  
IPBR  
RBR = ≤  
Ohmic value of the resistor:  
f004  
PPBR * tBR  
2T  
EBR  
T
PNBR  
=
=
Rated continuous power of the resistor:  
f005  
Attention! The value calculated here has to be considered carefully:  
the formula calculates an average power value which may be considerably different  
from the istantaneous power in case of very low duty-cycles.  
Normally, resistors are not able to sustain a peak power greater than 5 to 10 times their rated  
power. For this reason if the duty-cycles are less than 10%, the value calculated here can not  
be used as rated power of the resistor and considerations made at 4.1 and 6 have to be taken  
into account. Consult your resistor manufacturer for overload capability of resistors.  
1
4
—————— DIMENSIONING... AND CORRESPONDING... ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
Being normally n2 = 0 (stop), we will have that:  
1
2
EBR  
=
PPBR * tBR  
f006  
IPBU IPBR  
Braking unit features:  
f007  
This means that the peak current admissible by the 6KBU300-... must be equal or higher than the effective one.  
Then for the average current we will have:  
EBR  
tBR * VBR  
IAVBR  
=
IAVBU IAVBR  
f008  
Sample calculation  
Data:  
- AC Input voltage  
- Drive model  
3 x 460 V  
6KAV3015  
15 HP  
- Rated motor power  
- Rated motor speed  
- Moment of inertia of the motor  
(PM)  
(nn)  
(JM)  
(JL)  
(MS)  
(n1)  
(n2)  
(tBR)  
(T)  
3515 rpm  
0.033 kgm2  
0.95 kgm2  
10% of motor nominal torque  
3000 rpm  
- Moment of inertia loading the motor shaft  
- Friction of the system  
- Initial braking speed  
- Final braking speed  
- Braking time  
0 rpm  
10 sec  
- Cycle time  
120 sec  
We will have:  
JTOT= JM + JL = 0.033 + 0.95 = 0.983 kgm2 and  
∆ω = [2Π * (n1 - n2)] / 60 sec/min = 2Π * 3000 / 60 = 314 sec-1  
Rated motor torque:  
MM = PM / ω = (15 * 745.7) / ( 2Π * 3515 / 60) = 30.4 Nm  
it follows that  
n
MS = 0.1 MM = 3.04 Nm  
The braking energy is given by:  
EBR = (JTOT / 2) * (2Π / 60)2 * (n12 -n22) = (0.983 / 2) * (0.10472)2 * 30002 = 48509 Joules or Wsec  
2
4
—————— DIMENSIONING... AND CORRESPONDING... ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
But, if we want to take into account also the friction of the system, the braking energy that the braking unit will  
need to dissipate is lower. To do this we can calculate EB as follows:  
The required braking torque is  
Mb = (JTOT * ω) / tBR = 0.983 * 314 / 10 = 30.9 Nm  
In reality the friction torque “helps” the motor, so we obtain  
MbM = Mb - MS = 30.9 - 3.04 = 27.86 Nm  
The brake process average power is given by  
PAVE = (MbM * ω) / 2 = 27.86 * 314 * 0.5 = 4374 W  
And the new value of braking energy that we obtain in this way is  
New EBR = PAVE * tBR = 4374 * 10 = 43740 Joules or Ws  
which is obviously lower than the previous one.  
The peak braking power is given by  
PPBR = (JTOT * n1 * ω * 2Π) / (tBR * 60) = 9.7 kW then we continue with  
IPBR = PPBR / VBR = 9700 / 745 = 13A and  
RBR VBR / IPBR = 745 / 13 = 57 Ω  
Being IPBR = 13A, here we can already see that the unit 6KBU300-20 covers our needs. Now we have to  
choose the resistor:  
The nominal power of the resistor has to be  
PNBR = (PPBR * tBR) / 2T = (9700 * 10) / 240 = 404 W  
As we can see, the nominal power of the resistor is relative low due to a low duty-cycle (10 / 120) but the resistor  
must be able to withstand the energy that is applied to it during the 10 seconds of braking. This energy is 43740  
Joules. If we go on the table of normalized resistors, the type BRR 1K0T 49R has a nominal power that would  
be sufficient but the value of EBR is too low (21kWsec).  
For this reason our final choice is the type BRR 1K3T 31R that has EBR = 44kWsec.  
3
4
—————— DIMENSIONING... AND CORRESPONDING... ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
4.1. SIMPLIFIED DIMENSIONING OF THE RESISTOR  
In case all the above mentioned data were not available, it is possible to carry out the braking resistor calculation  
in a simplest but approximately way.  
This solution can lead to an overdimensioning of the resistor which has to be used.  
For the calculation of different resistor values (to use e.g. with different threshold intervention values of the  
braking unit) it is possible to use the following formula:  
VBR [V]  
RBR [] =  
IPBU [I]  
f011  
Where “VBR” means the intervention threshold of the braking unit and “IPBU” the max. peak current described  
in the table.  
Needing to calculate the value of the resistor for an inverter 6KAV3037 (100A peak current for the braking)  
supplied with 400V (intervention threshold 680V with S1-3 ON) we will have:  
680  
RBR  
=
= 6,8 ohm  
100  
f012  
This formula shows the ohmic value, while about the resistor power the following consideration have to be taken  
into account.  
The braking resistor is normally used with intermittent cycle; it will be possible in this way to use a resistor able to  
2
dissipate a costant power lower than the one given by the product RBR * IPBR  
.
To decide the overload factor the following diagram can be used (such diagrams can be supplied from the  
manufacturer of the resistor to use).  
RESISTANCE POWER  
1000  
100  
Pause time  
15 seconds  
30 seconds  
10  
1 minute  
5 minutes  
30 minutes  
1
0,1  
1
2
3
4
5
6
7
8
9
10  
OVERLOAD FACTOR  
4
4
—————— DIMENSIONING... AND CORRESPONDING... ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
To calculate the value of the costant power (or rated) of the braking resistor using this graphic, it will be possible  
to apply the following formula:  
regenerated power  
continuative power RBR  
=
overload factor  
f013  
Considering having to brake a 30KW motor with overload of 150%, the regenerated power will be at maximum  
45KW.  
Supposing a braking time of 5 seconds (overload time for the resistor) and 1 break minute, the graphic provides an  
overload factor of 3,9, so the rated power of the resistor will be:  
45000  
= 11.5 kW  
3.9  
f014  
NOTE:  
The use of the normalized resistors reported at chapter 6 it is strongly reccomended  
5
4
—————— DIMENSIONING... AND CORRESPONDING... ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
5. MINIMUM VALUE OF THE RESISTORS THAT CAN BE USED  
Model  
Value of intervention threshold  
640V 680V  
Minimum value of resistors  
400V  
745V  
6KBU300-20  
6KBU300-50  
6KBU300-85  
10 ohm  
4 ohm  
16 ohm  
6.4 ohm  
3.7 ohm  
17 ohm  
6.8 ohm  
4 ohm  
18.6 ohm  
7.5 ohm  
4.4 ohm  
2.4 ohm  
bu0040  
The ohmic value indicated in the table, represents the absolute minimum value of the resistor connectable to  
the different braking units in correspondence of the braking threshold set.  
In case these values would not be available, it might be possible to use higher ohmic values.  
E.g. with the braking unit 6KBU300-20 used with intervention threshold of 680V the indicated resistor value is  
17, if the commercial available ohmic value is 18, it will be allowed its use with no problem (don’t use  
16).  
The indication is for a best use of braking resistors when more parallelled resistors are used, case in which the  
ohmic values indicated in the table should not be available.  
ATTENTION!!  
Units are not protected against direct short-circuit between terminals CR, BR. This  
condition can lead to the destruction of the unit, if external DC fusing is not supplied.  
1
5
—————— MINIMUM VALUE OF OF THE RESISTANCES ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
6. STANDARD BRAKING RESISTORS  
In order to simplify the choice of the resistor that has to be used, here below the values of the normalized resistors  
are reported, calculated on a criterion for a typical use.  
POVL  
Overload power that can be regenerated by the inverter, equal to the rated power mul-  
tiplied by factor 1.36 (inverter’s overload = Icont x 1.36)  
PAVBR  
EBR  
tOVLBR  
tBR  
Average power dissipated by the resistor, where the duty cycle is equal to 10%  
Maximum instantaneous energy that the resistor can dissipate  
Maximum continuative braking time in overload conditions (POVL  
)
Maximum continuative braking time at drive rated load conditions  
PNBR  
Rated continuous power of the resistor which must be equal or greater than the average  
power PAVBR  
P,n  
PPBR  
EBR  
n
t
TBR  
TC  
The ohmic value of the normalized resistors has been calculated in order to assure the braking current for the limit  
use of 6KBU300, that is to say a 460Vac supply of the inverter (braking threshold 745Vdc).  
1
6
—————— STANDARD BRAKING RESISTANCES ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
GEI-100350A  
AV300  
BU300  
POVL  
PAVBR  
EBR  
tOVLBR  
tBR  
PNBR  
RESISTANCES OHMIC  
MARK  
VALUE  
[KW]  
[KW] [Kwsec] [sec]  
[sec]  
[KW]  
3003  
3005  
3011  
3015  
3022  
3030  
3037  
3045  
3055  
…-20  
…-20  
…-20  
…-20  
... -50  
…-50  
…-50  
…-50  
…-85  
4
0.5  
0.7  
1.5  
2
8.8  
14  
5
5
7
7
0.5  
0.8  
1.3  
4
BRR 500T 100R  
BRR 800T 68R  
BRR 1K3T 31R  
BDR 4K0T 23R  
BDR 4K0T 15R4  
BDR 4K0T 11R6  
BDR 8K0T 9R2  
BDR 8K0T 7R7  
BDR 8K0T 6R2  
2 x BDR 8K0T  
9R2  
100  
68 Ω  
31 Ω  
6.8  
15  
20  
30  
40  
50  
60  
75  
44  
3.5  
8
5
80  
11  
8
23 Ω  
3
120  
70  
6
4
15.4 Ω  
11.6 Ω  
9.2 Ω  
7.7 Ω  
6.2 Ω  
4
4
5.5  
10  
8
4
5
180  
220  
140  
7.5  
6
8
6
8
7.5  
4.5  
6
8
3075  
3090  
3110  
3132  
3160  
3250  
3315  
…-85  
100  
120  
150  
180  
10  
12  
2 x 180  
2 x 220  
2 x 140  
2 x 350  
2 x 350  
3 x 350  
3 x 350  
7.5  
6
10  
8
2 x 8  
2 x 8  
9.2 Ω  
7.7 Ω  
6.2 Ω  
5.1 Ω  
5.1 Ω  
5.1 Ω  
5.1 Ω  
2 x BDR 8K0T  
7R7  
2 x …-50  
2 x …-85  
2 x …-85  
2 x …-85  
3 x …-85  
3 x …-85  
2 x BDR 8K0T  
6R2  
15  
4.5  
6
6
2 x 8  
2 x BDR 12KT  
5R1  
18  
8
2 x 12  
2 x 12  
3 x 12  
3 x 12  
180 *  
(218)  
272 *  
(340)  
272 *  
(340)  
2 x BDR 12KT  
5R1  
18  
6
8
3 x BDR 12KT  
5R1  
27.2  
27.2  
6
8
3 x BDR 12KT  
5R1  
6
8
bu0055  
NOTE:  
the power ratings indicated with (*) have a value lightly below to the one calculated for POVL  
(value between brackets) in order to avoid the introduction of further values of resistors.  
Furthermore it must be take into consideration that with high power ratings as these ones, the  
dynamic performances are generally lower and could even require the use of a regenerative  
unit on the DC bus.  
For 3250 and 3315 sizes, the use of the Line Regen Converter RS-300 should be more convenient.  
Every resistor used having different features by the ones above mentioned, must be rated to support the power  
POVL for a time equal to 1/10 of the one of an hypothetical cycle, where after the overload follows a period at zero  
power for 9/10 of the whole time (10% duty cycle).  
POVL x 0.1 T = PAVBR x T  
The maximum duration of the braking time (and consequently the total duration of the cycle) will be determined  
by the maximum energy pulse EBR admitted for the resistor during the braking moment, according to the following  
relation:  
tOVLBR and tBR = 0.1 T = EBR / POVL  
Since the working temperature of the resistor is not known, the resistor itself must be provided with a normally  
closed thermal dry contact (Klixon) see chapter 3.5.  
2
6
—————— STANDARD BRAKING RESISTANCES ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
7. EXTERNAL PANEL MOUNTED DC FUSE  
Recommended fuses that must be inserted on terminals C and D.  
Model  
Fuses  
A70P80  
FWP80  
6KBU300-20  
A70P150  
FWP150  
A70P200  
FWP200  
6KBU300-50  
6KBU300-85  
bu0050  
Fuse Manufacturers:  
A70P  
FWP  
Gold Shawmut  
Bussman  
1
7
—————— SUPERFAST DC FUSE TABLE ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6KBU300  
8. BLOCKS DIAGRAM  
9
8
7
6
5
RBR  
4
3
2
1
A
D
B
C
E
1
8
—————— BLOCKS DIAGRAM ——————  
Download from Www.Somanuals.com. All Manuals Search And Download.  
We bring good things to life.  
GE Industrial Control Systems  
GEI-100350A Rev. 2.0 (6/98)  
Download from Www.Somanuals.com. All Manuals Search And Download.  

Eagle Electronics Fish Finder 500CDF User Manual
Electro Voice Microphone C090 User Manual
Electro Voice Portable Speaker PRO 12 User Manual
Eton Radio G4000A User Manual
Excalibur electronic Games VR07 User Manual
Extron electronic Stereo System MHR 6 User Manual
Fisher Price Baby Monitor P1384 User Manual
Fisher Price Baby Toy C1857 User Manual
Gemini Stereo Amplifier PA 7000 User Manual
Generac Power Systems Portable Generator 04758 0 User Manual