Rockwell Automation FlexPak Plus NRG DC Drive - Manual (Page 15)

WARNING
14
DANGER
THE MACHINERY BUILDER IS RESPONSIBLE
FOR INSURING THAT DRIVEN MACHINERY, ALL
DRIVETRAIN MECHANISMS NOT SUPPLIED BY
RELIANCE ELECTRIC AND PROCESS LINE MAĆ
TERIAL ARE CAPABLE OF SAFE OPERATION AT
MAXIMUM SPEEDS. FAILURE TO DO SO CAN
RESULT IN DESTRUCTION OF MECHANISM OR
MATERIAL AND FLYING FRAGMENTS, ENĆ
DANGERING OPERATING PERSONNEL.
3.7 Overspeed - The DĆC motor is performance rated
to develop nameplate horsepower when operated at
rated base speed. The base speed of the DĆC motor is
defined as the speed at which the motor will operate
when excited with rated armature terminal voltage,
rated shunt field. current and when coupled to a driven
load requiring rated torque. The actual speed at which
the motor will run under these conditions will fall within
a range of +7.5% from nameplate base speed. Typical
base speeds for industrial DC machines include 650,
850, 1150, 1750 and 2500 RPM.
Many DĆC machines are also performance rated to opĆ
erate above base speed in a constant horsepower" or
field weakened" mode. These DĆC machines may be
incorporated into adjustable speed drive systems
which allow controlled reduction in shunt field current
while maintaining rated armature terminal voltage.
When so operated most of these motors will deliver it's
rated horsepower at any speed between base speed
and the indicated maximum field weakened speed. A
DĆC machine with an 1150 RPMbase speed and the caĆ
pability to be operated to 1950 RPMin a field weakened
mode will be nameplated 1150/1950 RPM.
Although rarely encountered, a single component failure
may occur within the drive controller that can apply arĆ
mature voltages in excess of 100% rated armature voltĆ
age to the motor, causing the motor speed to significantĆ
ly exceed either base speed or rated field weakened
speed. Under these conditions, motor speed may be unĆ
responsive to the operators speed potentiometer and/or
other speed references. Should such a condition occur,
the drive must be quickly stopped using the appropriate
stop" pushbutton, and the fault condition located and
corrected before returning the drive to operation.
During such a condition, the DĆC motor, associated driĆ
vetrain equipment, driven machinery and the driven
process itself may be subjected to operating speeds
well in excess of normal rated speeds. As such, the folĆ
lowing considerations are necessary:
All Reliance Electric Drive packages manufactured after
February 1,1982 (where the motor and controller are
both manufactured by Reliance Electric and furnished
together on the same Reliance Sales Order) have a maxiĆ
mum safe speed (M.S.S.) in excess of the speed that
would occur under the single point failure discussed
above or are equipped with a speed limiting device
such as tachometer loss and overspeed protection,
armature voltage relays or a motor overspeed switch.
(Assuming the drive equipment is operated on three
phase power supplies listed below.)
Rated
Armature
Voltage
Rated AĆC
Line
Voltage
Maximum AĆC
Line
Voltage
240 volts DĆC
500 volts DĆC
600 volts DĆC
230 volts DĆC
460 volts DĆC
550 volts DĆC
253 volts AĆC
506 volts AĆC
605 volts AĆC
If the above AĆC and DĆC voltage conditions are not apĆ
plicable to the installation in question. then it becomes
the responsibility of the user to calculate attainable moĆ
tor speed under the single component failure condition
using the procedure outlined below and to verify that
this speed does not exceed the M.S.S. of the motor.
CHART I
VAC = Nominal RMS lineĆtoĆline voltage
S
B
= Base speed at full field and rated armature
voltage
Eg (NL) = Armature voltage no load
MSS = Max safe operating speed
VAC
S
MAX
= 1.49 x Eg (NL) x S
B
The motor Maximum Safe Speed, which varies as a
function of motor frame diameter, are listed below. ExĆ
amination of the motor nameplate may indicate a
M.S.S. slightly different for that specific machine. In that
case, motor nameplate M.S.S. takes precedence.
Reliance
Motor
Frame
Size
Maximum
Operating
Speed,
RPM
Reliance
Motor
Frame
Size
Maximum
Operating
Speed,
RPM
56
B160
B180ATZ
B210ATZ
B250ATZ
B280ATZ
B320ATZ
B360ATZ
5500
5000 5200
5000
4500
4500
4500
3600
3400
B400ATZ
B500ATZ
B580ATZ
B680ATZ
B840ATZ
B960ATZ
B1200
B1400
B1600
2760
2650
2475
2100
1720
1600
1600
1440
1200
CAUTION: Motor frames not listed in the above tabĆ
ulation, or motors manufactured by others, may not
operate within their maximum safe speeds, when a
single point failure occurs. In these cases, it beĆ
comes the responsibility of the user to verify the moĆ
tor maximum safe operating speed and confirm
(using the procedure above) that attainable motor
speed under a single point fault condition falls beĆ
low the maximum safe operating speed.