Contactors for critical applications

AC and DC contactors up to 4,800 V and 2,000 A

With the the introduction of DC networks in manufacturing, as well as the rapid growth of renewable energies and the electric automobile motor industry, the switching of high DC loads is gaining in significance and underscoring the need for high-quality DC contactors. Building upon our experience in railway technology, Schaltbau produces highly reliable, outstanding contactors for all fields of use in which a load circuit has to be switched on and disconnected securely. Designed to IEC specifications, our wide variety of AC and DC contactors in stock range from contactors for low-voltage devices, such as batteries, through to high-voltage power contactors up to 4,800 V and 1,100 A. We develop DC contactors for, among other uses, industrial storage systems, battery test systems, car batteries and electrical bus motors.

Why arc quenching is so demanding with DC contactors

A DC or AC contactor (or switching contactor) is an electrically or electromagnetically (in special applications also pneumatically) operated switch for large electrical loads. The main contact is located inside the main circuit of the device, while auxiliary contact is found inside an auxiliary circuit and actuated mechanically by the switching device – serving to reduce coil current after the device switches off. The contactor includes a coil input (driven by DC or AC supply), with the coil energized by the same voltage as the motor the device is controlling or controlled with a lower coil voltage.

Whereas a general-purpose relay is nor designed to be directly connected to high-current load devices, both DC contactors and AC contactors can switch large loads remotely via control lines. When a control voltage is applied to the coil of the instrument, the magnetic field pulls an electrical bridge into an active state – the main contacts close. Without control voltage, springs in the contactor restore the initial state of the load circuit – the contact path is open again.

Unlike a general-purpose relay, contactors galvanically isolate the electrical drive train from the power supply when it is switched off, with an auxiliary contact reducing coil current after the contactor closes.

If switching off takes place under load, an electric arc is generated in the contactor. In DC voltage applications, extinguishing this arc is comparatively challenging, as no zero crossing of the voltage occurs here. Our DC contactors have effectively overcome this challenge, making arc suppression one of our products’ most notable attributes.

The electric arc in the contactor produced can only be controlled if different effects interact skillfully. Only then can short arc lifetimes – and thus fast switch-off times – be achieved. Thanks to our patented contactor process, this is a key feature of our DC contactors.

The formation of this so-called switching arc has two main effects: Firstly, current continues to flow despite the contacts being open, as the plasma has a high electrical conductivity. And secondly, very high temperatures of up to 20,000 Kelvin occur, which can cause damage to the contacts of the DC contactor as well as to surrounding system parts.

Unlike lower-powered relays, various measures are present in our DC contactor to counteract this. It is particularly important to move the arc away from the actual contact surfaces and to extinguish it. This is mainly done by means of an arcing chamber in which the electric arc is elongated, cooled and thus extinguished.

The arcing chamber is thus the central functional unit in DC power contactors.

Find contactors for your application

Device type
Nominal voltage
Thermal current
Number of poles
Type of voltage
Industry
CP – Modular and compact switchgearCP – Modular and compact switchgear

1 pole bi-directional high-voltage contactors, disconnectors, changeover switches for DC and AC

Do you have questions about this product?CP – Modular and compact switchgearContactors
5450
CF – Multipole AC power contactorsCF – Multipole AC power contactors

Modular and compact AC power contactors for inverter-fed AC drives with higher frequencies

Do you have questions about this product?CF – Multipole AC power contactorsContactors
5714
CT – power contactors for AC and DC (bidirectional) up to 4.8 KV and 1,100 ACT – power contactors for AC and DC (bidirectional) up to 4.8 KV and 1,100 A

Combination of electric and permanent-magnetic blowout in one contactor.

Do you have questions about this product?CT – power contactors for AC and DC (bidirectional) up to 4.8 KV and 1,100 AContactors
4996
CA – power contactors for AC applicationsCA – power contactors for AC applications

Triple pole contactors up to 4,800 V, 800 A and 400 Hz.

Do you have questions about this product?CA – power contactors for AC applicationsContactors
2833
CH1130 – compact contactor for AC and DC (semi-bidirectional) up to 4.8 kVCH1130 – compact contactor for AC and DC (semi-bidirectional) up to 4.8 kV

Redesign based on CT technology.

Do you have questions about this product?CH1130 – compact contactor for AC and DC (semi-bidirectional) up to 4.8 kVContactors
4614
CL – Single-pole, double-pole and triple-pole contactors CL – Single-pole, double-pole and triple-pole contactors

AC and DC contactors up to 2200 V and 250 A.

Do you have questions about this product?CL – Single-pole, double-pole and triple-pole contactors Contactors
879
CH715, CH815 – 3 kV contactorsCH715, CH815 – 3 kV contactors

Contactors for AC and DC up to 3000 V and 50 A for rail.

Do you have questions about this product?CH715, CH815 – 3 kV contactorsContactors
1381
CH500, CH800, CH801 – 3 kV contactorsCH500, CH800, CH801 – 3 kV contactors

Contactors for AC and DC up to 3000 V and 80 A for rail.

Do you have questions about this product?CH500, CH800, CH801 – 3 kV contactorsContactors
1388
CH1030 – 3 kV contactorsCH1030 – 3 kV contactors

Contactors for AC and DC up to 3000 V and 120 A for rail.

Do you have questions about this product?CH1030 – 3 kV contactorsContactors
1393
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