Application field of PEM CWT Rogowski coil

In the past 20 years, CWT has been supplied to major electrical engineering companies and leading research institutions around the world. This versatile instrument has been widely used in various applications, such as:

Semiconductor switching waveform

CWT can be used to measure various power semiconductors, such as switching losses in power semiconductors or checking whether the inductance of the line does not exert excessive pressure on the IGBT or MOSFET.

CWT is non-intrusive, only injects a small amount of PH into the main loop, its high-frequency bandwidth is greater than 10MHz, has a predictable known measurement delay, and is thin and flexible, so it is easy to insert or even difficult to install. Reach all parts of the circuit.

CWT 50μs 3kA peak value, 100ns falling edge with 300ns coil and 800MHz (3dB)) coaxial shunt CWT30 

Application field of PEM CWT Rogowski coil

Large AC currents in generators, motor drives, and power supplies

Unlike other forms of current measurement, the size of the sensing coil (Rogowski coil) has nothing to do with the size of the measured current. Therefore, for large currents, the size of the Rogowski coil can be selected to suit the diameter of the conductor. In this case, the probe based on magnetic materials such as the Hall effect becomes more and more cumbersome and expensive at higher rated currents. In the 1000A range, there is really a no better choice than PEM's Rogowski current sensor.

Pulse power application

Rogowski coil using PEM:

To monitor the current in the kick electromagnet in the large particle accelerator.

In the laser power supply

In the "superconducting fault current limiter" (low-temperature applications)

High-frequency sine wave applications such as induction heating

CWT can measure large sinusoidal currents at high frequencies with high accuracy and predictable phase response. This is very important for applications such as induction heating, where it is very important to control zero crossings in induction heating, or for high-frequency power measurement.

For example, CWT15 (with a rated peak value of 3000A) can measure continuous sinusoidal currents up to 1000A at frequencies exceeding 100kHz. PEM provides a custom-designed version of CWT for higher frequency applications.

Lightning strike measurement

CWT has a wide bandwidth, high peak current rating, and high di/dt capability (40kA/μs or greater for custom designs), and is a useful tool for monitoring lightning strikes. These shocks are usually specified as 8/20μs or 10/350μs waveforms, so current sensors require both high-frequency performance in the MHz range and negligible droop characteristics, that is, a low-frequency bandwidth of less than 0.1Hz.

In addition to our standard CWT units, PEM also provides custom-designed coils with a maximum circumference of 20m for monitoring lightning strikes in large structures such as wind turbines.

Measure small AC currents in the case of large DC currents (for example, capacitor ripple)

Rogowski current sensors do not measure the DC component of current. However, unlike CT or Hall effect devices, they do not contain magnetic materials and are therefore not affected by direct current. Therefore, it is possible to use a small, flexible Rogowski coil to measure small AC currents under high DC current conditions, while sensors based on magnetic principles are expensive and bulky, and cannot prevent saturation effects. One such common application is to measure ripple currents in capacitors where the main current is DC or slowly changing.