SWL Liquid-Cooled Sine Wave Filters

Superior cooling technology and the highest power density: The ultimate motor protection solution

Product Overview

CTM Liquid Cooled Sine Wave Filters transform the output of Variable Frequency/Speed Drives (VFDs or VSDs) from a Pulse-Width Modulated (PWM) square wave with voltage spikes and high frequency harmonics to a near perfect sinusoidal waveform. CTM’s patented liquid cooled technology traps and removes 97% of the filter’s heat in the highest power density solution available to the market. The largest companies in the world rely on CTM technology, with more than 200,000 installed units in some of the harshest environments on the planet.

Liquid Cooled Advantages

  • Highest power density
  • Lowest audible noise
  • Sealed design for harsh conditions
  • Thermally isolated from ambient

Sine Wave Filter Applications

  • Increase system life by reducing harmonic distortion
  • Better motor protection for motor windings and bearings
  • Increase maximum allowable lead length between motor and drive (up to 15,000 feet)
Harmonic Voltage Distortion

<5% @ 2 kHz

Voltage Range

Up to 500 V

Fundamental Frequency

6 - 70 Hz (higher with de-rating) - For up to 400 Hz applications, see S4L Series Sine Wave Filters

Switching Frequency

2 - 20 kHz Above 8 kHz, contact CTM for application verification

Motor Cable Length

Up to 15,000 feet

Current Range

130 - 1,440 A

Overload Capability

200% rated current for 1 minute

Maximum Coolant Temperature

50 °C (122 °F) (higher with de-rating)

Approved Coolants

Drinking water Water-glycol mixture For R134A, contact CTM

Agency Recognitions

cЯUus 1446

Plumbing Material Options

Aluminum (standard) Copper

Heat Removal

97% to Liquid Coolant 3% to Ambient Air

Maximum Ambient Temperature

65 °C (149 °F)

Maximum Altitude

No Limit

Product Highlights

  • Motor Protection: Harmful square waves, voltage spikes, and harmonic distortion are all filtered from the inverter output, reducing motor heating, wear, and winding stress, providing critical motor protection.
  • Maximum Motor Lead Length: Reflected voltage waves occur when motor lead lengths reach or exceed a characteristic length of the system, which is dependent on the voltage rise times (dV/dt) in the cabling. By filtering the PWM waveform to a near perfect sinusoidal waveform, CTM sine wave filters minimize dV/dt, allowing for longer motor lead lengths (up to 15,000 feet in certain applications).
  • Increase Motor Longevity: By reducing motor ripple current, CTM sine wave filters reduce motor heat, noise and vibration, thereby extending motor life. Additionally ripple current reduction eliminates torque ripple.
  • Filter Reliability: CTM Filters maintain lower temperatures, increasing life and reliability. Sealed inductor designs further increase product reliability.

Liquid Cooled Advantages

  • Highest Power Density: Superior heat removal technology enables smaller magnetics, yielding the highest power density reactors available. Low surface temperatures eliminate clearance requirements, further increasing “effective” power density.
  • Thermal Isolation: With up to 97% of heat removed through the coolant, liquid cooled reactors have negligible effects on cabinet air temperature. No climate control required.
  • Sealed Design for Harsh Environments: RPL Reactors are environmentally sealed, creating an extremely rugged and reliable design ideal for use in the harsh environments.
  • Extremely Low Audible Noise: Due to superior materials and geometric shapes, magnetostriction-induced noise is significantly lower in CTM Reactors. When combined with a sealed package, the result is a nearly silent solution.

Thermal Isolation

CTM liquid cooled reactors will have negligible temperature effects when installed in an existing cabinet. Liquid cooled inductors are thermally isolated from their enclosures, meaning a majority (97%) of the heat is removed directly through the liquid coolant.

In this example, both an air cooled and a liquid cooled reactor are sized for a 600 HP motor application; both reactors are identically 99.5% efficient (0.5% power loss). The air cooled reactor rejects 3,000 watts to the cabinet air, while the equivalent liquid cooled reactor only rejects 90 watts to the air. The remaining 2,910 watts are removed directly by the liquid coolant.

As can be seen in the graph, in a typical NEMA 3R cabinet, installation of an air cooled reactor will increase cabinet air temperature by 20.9°C . The equivalent liquid cooled reactor raises cabinet air temperature by only 1.4°C. The low temperature rise provided by liquid cooled reactors yields increased reliability for all electronics within the cabinet. Low surface temperatures also allow the liquid cooled reactor to smaller clearances, increasing effective power density further.

SWL Liquid-Cooled Sine Wave Filters