Cutler Hammer Type FD Thermal-Magnetic Circuit Breakers

Cutler Hammer is a brand of circuit breakers that is also part of the Eaton Power Company’s global product series.

The Cutler Hammer brand was founded by Harry Cutler and Edward Hammer in 1893. Originally, Cutler Hammer specialized in designing electric starters, speed regulators and field rheostats.

Over the next several decades, Cutler Hammer patented a variety of electrical products, beginning with the first automatic motor starter in 1900, to a total of 28 patents by the end of the 1930s. By 1978, Cutler Hammer was incorporated into the Eaton Company to become part of a global brand.

Today, the company manufactures a range of circuit breakers made for both commercial and domestic use. Additionally, the Cutler Hammer FD breakers have become one of the most popular brands on the market, due to the company’s quality control standards.

About Thermal-Magnetic Circuit Breakers

The purpose of all circuit breakers is to interrupt current flow to protect electrical circuits from excess currents. Thermal-magnetic circuit breakers are no exception. In fact, they stand out among other circuit breakers because they have the fastest speed of current interruption, with some breakers having the capacity to stop the current in as little as four milliseconds.

Made with two components, thermal-magnetic circuit breakers contain a contact strip that is sensitive to changes in temperature. This strip protects the circuit against excess currents.

The other component in a thermal-magnetic circuit breaker is the magnetic part. Its function is to protect the motor circuit from instant surges of current.

Together, the thermal-magnetic strip, along with the magnetic part, help protect circuit breakers from large surges in current and high periods of excess current.

Cutler Hammer Thermal-magnetic Circuit Breakers

Cutler Hammer carries a range of circuit breakers under its name. From molded case breakers to insulated case circuit breakers, the brand can be counted on for its impeccable design and reliability.

One of Cutler Hammer’s most popular lines of circuit breakers is the type FD thermal-magnetic circuit breaker. They are designed with non-interchangeable trip units, with the terminals on the load-end only.

FD3200 Thermal-magnetic Circuit Breaker

Cutler Hammer’s FD3200 is a triple pole, thermal-magnetic circuit breaker. This means it can be connected to three different circuits and protect them all at the same time. It can withstand a voltage of 600V and an amperage of 200A.

The FD3200 also has a short circuit interrupting capacity of 35kA at 480VAC, which means it can safely interrupt 35kA of current at a voltage of 480V for AC currents.

FD3030 Thermal-magnetic Circuit Breaker

Similar to the FD3200, Cutler Hammer’s FD3030 is also a triple pole thermal-magnetic circuit breaker with a voltage rating of 600V. Its only difference is that it is rated for smaller currents up to 30A.

Identical to the FD3200, the FD3030 has a short circuit interrupting capacity of 35kA at 480VAC, meaning it can interrupt 35kA of current at a voltage of 480V for AC currents.

FD3150 Thermal-magnetic Circuit Breaker

The FD3150 by Cutler Hammer is another triple pole thermal-magnetic circuit breaker with a voltage rating of 600V. However, it differs from its counterparts, as it has an amperage rating of 150A, which falls within the FD3200 and FD3030.

Also, identical to its counterparts, the FD3150 has a short circuit interrupting capacity of 35kA at 480VAC, so it can interrupt 35kA of AC current at a voltage of 480V.

FD2200 Thermal-magnetic Circuit Breaker

The FD2200 by Cutler Hammer is a thermal-magnetic circuit breaker that is different from the other models. This is because it only has two poles, allowing it to protect two independent circuits instead of three.

Additionally, the FD2200 has a voltage rating of 600V and an amperage rating of 200A. It also has a short circuit interrupting capacity of 35kA at 480V.

FD3225 Thermal-magnetic Circuit Breaker

The FD3225 by Cutler Hammer is a thermal-magnetic circuit breaker with three poles, a voltage rating of 600V and an amperage rating of 225A. It can protect three different circuits at the same time.

Like its counterparts, it also has a short circuit interrupting capacity of 35kA AC current at 480V. It is a molded case circuit breaker, using a combination of trip units to protect against thermal overloads, short circuits and ground faults.

Final Thoughts

Cutler Hammer has been designing electrical components for over a hundred years. Some of their most popular circuit breakers are in the FD thermal-magnetic circuit breaker line. These breakers are all designed with non-interchangeable trip units. They also feature a short circuit interrupting capacity of 35kA at 480V, as well as similar voltage ratings.

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