SURGE PROTECTION CAPACITORS · RC / CR SUPPRESSORS
Surge capacitors that protect motors, transformers and switchgear from switching transients.
Every high voltage installation with power transformers, dry-type transformers, and HV motors is exposed to switching transients - most severely from the multiple switching and re-striking of vacuum circuit breakers. Those transients cause steep, high-magnitude voltage spikes that stress and eventually fail equipment insulation.
Surge capacitors - also called surge suppression capacitors, surge suppressors, or RC / CR suppressors - are connected in parallel with HV motors and transformers to control this. They slow the rate of rise of the transient and eliminate current chopping, voltage escalation, and repetitive pre-ignition. Adding a surge capacitor reduces the high-frequency oscillating current through the breaker from hundreds of kHz to a few kHz. Where an RC suppressor is used, a series resistor is added to damp the oscillation - the resistor is a low-inductance type, its wattage set by the peak discharge and rated current.
Marxelec surge capacitors use a BOPP film dielectric, 99% purity aluminium foil, and NPCB oil, in low-loss, low-inductance, leak-free construction to national and international standards. Units are built for system voltages from 3.3 kV to 36 kV, with impulse withstand up to 190 kVp.
Individually tested before dispatch.
The full technical envelope. Each unit despatched carries a signed test certificate naming the measured value of every line below.
Parameter
Value
Notes
Dissipation factor (tan δ)
Low-loss, low-inductance · value of < 0.0002
Series resistor (RC variant)
Low-inductance type
Wattage set by peak discharge + rated current
Frequency
Power frequency
50 / 60 Hz
System voltage
Cap. rated voltage
Impulse withstand
Capacitor rating
3.3 kV
6 kV
55 kVp
0.25 µF, 0.5 µF
7.2 kV
12 kV
75 kVp
0.25 µF, 0.5 µF
12 kV
18 kV
100 kVp
0.25 µF
24 kV
28 kV
140 kVp
0.125 µF, 0.25 µF
36 kV
40 kV
190 kVp
0.125 µF, 0.25 µF
Parameter
Value
Notes
Ambient operating range
-20 to +50 degree Celsius &
-40 to +50 degree Celsius
Cooling
Natural air
Parameter
Value
Notes
Dielectric
BOPP
99% Al foil, NPCB oil
Container (≤ 24 kV)
Metal, single bushing
Impulse withstand up to 24 kV class
Container (36 kV)
Two units in series
Mounted on base / support insulator
Insulated container
Available, all voltages
With required impulse withstand
Three-phase single units
Up to 12 kV system
Weight
Per rating
Parameter
Value
Notes
Design & test standards
IS11548
Manufacturing
Class 100 clean room (winding)
Per facility
Applications this capacitor is built for.
HT motor protection
Parallel protection against switching spikes
Transformer protection
Power and dry-type transformer insulation protection
Arc-furnace transformers
Protection against multiple breaker switching
Switchgear & generators
Steep-wavefront transient suppression
Vacuum-breaker circuits
Reducing re-striking oscillation frequency
Lightning / surge suppression
High-magnitude spike and surge suppression
Surface mining
Iron ore, copper, coal operations
Chemical & petrochemical
Process-plant motor and transformer protection
Induction & arc furnaces
Furnace switchgear protection
Built to the required form factors.
Every unit is built to the customer's mechanical specification. Container, shape, and termination are confirmed at order stage. Below - the standard configurations we build.
Tested against the application inspection plan.
In the applications a unit goes into, a sampling failure is a deployed failure. Every unit ships with a signed test certificate listing the measured value of each test below.
Capacitance & dissipation factor
Capacitance to tolerance -5 to +10% | tan δ against
spec < 0.0002
Impulse withstands
Impulse voltage test to the rated kVp for the system voltage.
Resistor verification (RC)
Series-resistor value and inductance check.
Dimensional
Inspection per drawing.
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Share the details you have: voltage, capacitance, frequency, current, duty cycle, cooling method, application context, drawing, existing part number, nameplate photograph or failed sample details. The first message does not need to be complete. It needs to start the technical review. Our team will respond within two working days.
Marxelec Energy Pvt. Ltd.
Plot No. L-49, MIDC Kupwad
Sangli Miraj Kupwad
Sangli, Maharashtra 416436
India
response@marxelec.com
+91 91686 18452