The Problem: Over-Voltage Spikes @ Motor Terminals (Reflected Waves)
0 50 100-500
-300
-100
100
300
500
700
900
1100
1300
Time (microseconds)P
ea
k V
olta
ge
at
mo
t. t
erm
. 1
37
0V Failure Threshold
(>1000 Volts)
• Significant motor failures (insulation failure) caused by reflective wave spikes • High dV/dt on PWM pulse creates over-voltage spikes at motor terminals.• Occurs with cable lengths >50 feet (between drives and motor).• Per NEMA MGI Part 30 and VDE 530, motors rated for 600V or less withstand a peak voltage of only 1000V.• Existing solutions (A-B Terminator, TCI series filters) have performance limitations.
MDrive
Reflected wave at motor terminals
The Solution: Reflected Wave Trap (RWT)
Without RWT
With RWT
Patented RWT installed at motor terminals: prevent motor damage/failures
1. One Size Fits All!
Only one model required for• 208 to 480 Volt applications• any H.P. motor• any drive/motor manufacturer
2. Two Enclosure Styles
Benefits of the Cutler-Hammer RWT
• NEMA 1 • NEMA 4X; Class I, Div 2 for hazardous environments
3. Superior Clamping
0 100 200-500
0
500
w/ RWT Time (micro seconds)
Pe
ak
volta
ge
at
mo
tor
term
ina
ls (
V)
With RWT
480 Volt Application
0 100 200-500
0
500
1000
w/o RWT Time (microseconds)
Pea
k vo
ltage
at m
otor
term
inal
s (V
)
Without RWT
Benefits of the Cutler-Hammer RWT (continued)
4. Status Indicator Light
• Not available with competitor models • Status indicator turns “OFF” if unit fails
5. Cost Effective, Easy to Install
Benefits of the Cutler-Hammer RWT (continued)
• Easy installation for retrofit and new systems • Mount within 25 feet of motor• Lower energy losses
6. The “Coolest” Solution • A-B normal operating temperature: 125 - 220°C (safety hazard, limits cable length, higher power losses) • C-H Reflected Wave Trap normal operating temperature: < 60°C for NEMA1; <90°C for NEMA 4X
Reflected Wave Solutions:Comparison of Heat Sink Temperatures
0
50
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150
200
250
Tem
pera
ture
(Cel
cius
)
A-B @216°C
C-H @ 90°C
Surface Temperature (degree’s Celsius)
Benefits of the Cutler-Hammer RWT (continued)
0100200300400500600700800900
1000
Mo
tor
Lea
d
Len
gth
(ft
)
480 Volt Drive: Reflected Wave ProtectionTechnology Comparison
competitor RWT (40 degree ambient) RWT (25 degree ambient)
Extended Protection with RWT
0 6 12Drive Speed (kHz)
CompetitorPerformance
• Higher carrier frequency:operates up to 12 kHz (compared to 2 to 6 kHz for competitor design)• Flexibility of operation: enables longer cable lengths between drive and motor•Eliminates cable degradation due to over voltage
7. Longer Cable Lengths, Faster Carrier Freq.
Benefits of the Cutler-Hammer RWT (continued)
R C N e t w o r k s R W T
O p e r a t i n gF r e q u e n c y
T y p ic a l ly < 6 k H z O v e r 1 2 k H z
P o w e r L o s s / H e a t i n g C o n s t a n t c u r r e n td r a w
C u r r e n t d r a w o n lyw h e n p e a k e x is t s
C a b l e L e n g t h L im i t e d d u e t o d r iv elo a d in g
L e s s c u r r e n t m a k e slo n g e r le n g t h sp o s s ib le
P e a k V o l t a g e I n c r e a s e s w i t hc a b le le n g t h
C o n s t a n t f o r c a b lele n g t h
The RWT is patented by Cutler-Hammer
Why RWT Technology?
Overview of Reflected Wave Solutions
Advantages Disadvantages
SERIES DEVICES Line Reactor LC Filters
Cost advantage on 1-10 HP
motors Can be used if motor is in
hazardous environment
voltage and torque reduction must be sized to motor hp higher cost for large motors complexity and losses
PARALLEL DEVICES(motor termination) Line Terminating
Impedance (RC filterby A-B)
Clipping device(RWT)
no voltage drop device can be used universally
on all sizes of drives
better peak voltage suppression device can be used universally
on all sizes of drives Cost effective (>15 HP)
high power losses carrier frequency limited not always suitable for small drives not applicable on deep wells
not applicable on deep wells
Additional Information on RWT & Drive Applications
RWT brochure (B.037F.01.S.E)Specification Guide (TD.37F.02.T.E)Commercial Article on RWT (AP.037F.01.T.E.)Installation & Operating Guide (TD-37F.01.T.E)Industry Articles (contact Surge Protection product line - attn Satendra Prasad)
Application assistance: Cutler-Hammer Drive Sales Managers
Stock/Price: Vista registered (stocked in Spartensburg)