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    • Applications
      • Industrial Automation & Production Equipment
      • Semiconductor & Test Equipment
      • Robotics, Robot Cells & Mobile Robots
      • Food, Beverage & Process Equipment
      • Life Sciences, Medical & Laboratory Equipment
      • Commercial, Self-Service & Public-Use Equipment
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      • Data Centers & Digital Infrastructure
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      • The Design Path
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    Schaltbau · Power it

    DC switching that breaks under load

    A battery bus never crosses zero, so the contactor has to clear the arc itself. Schaltbau DC contactors do it with permanent-magnet blowout in an open chamber. There is no gas fill to age, current flows in either direction through one device, and the parts that wear can be seen and replaced.

    Founded in Munich in 1929, Schaltbau has built rail switchgear ever since, and that design now goes into battery storage, charging, vehicles and test benches. Dynamic is the Schaltbau rep for Northern California and Northern Nevada.

    See the contactorsSend us your voltage and current
    Schaltbau C300 series single-pole DC contactor
    1,500 V, both directionsC303: 500 A continuous, bidirectional, in an open chamber with no gas fill.
    5,000 A for 20 msWhat the C303 carries without welding shut.
    To 3,000 VCT series contactors with contact tips and arc chute built to be replaced.
    UL RecognizedC310 and C320 to UL 60947-4-1 under file E116641.

    Where we put Schaltbau to work

    Three places the DC bus has to be broken safely

    In a modern battery, charger or converter the power electronics do the routine switching. The contactor has two jobs: carry current at low, stable contact resistance, and give a real galvanic break that interrupts a fault when it has to. Those are the jobs Schaltbau designs for.

    Battery storage and DC buses

    The same contactor sits in the path for charge and discharge, has to isolate the bus on command and break a fault when it comes. Bidirectional switching at 1,500 V class is the core of the C300 and C310 families, with a precharge coil option for the main-plus-precharge topology.

    C303, C310 and C320; mirror contact to IEC 60947-4-1 Annex F for the BMS or safety controller.

    Charging and vehicles

    Megawatt-class charging pushes continuous current past what the 500 A tier carries, and an on-vehicle disconnect has to survive shock and vibration all day. Schaltbau covers both ends of the cable, and the connector in between.

    C305 at 1,500 A and C330 at 2,000 A stationary; C800 family to ISO 16750-3 on the vehicle; HV connectors to 1,000 V DC and 470 A.

    Test benches and DC grids

    Benches and industrial DC grids need higher voltage, higher current or several coordinated switching paths, and they get opened and closed far more than a pack isolator. Serviceable contacts change the cost curve there.

    C320 to 1,000 A continuous; CF configurable to six poles; CT to 3,000 V with replaceable contact tips.
    Ask which life number. A headline cycle count is usually mechanical life, with almost no arc. For a pack or bus isolator, the number that matters is break life at your DC voltage and current. Ask for both lines, and ask whether the contact set is field-replaceable. The longer version is in our note on the specification metric.

    What Schaltbau makes

    Four contactor families, and the parts around them
    Schaltbau C300 series DC contactor
    01

    C300 family

    The workhorse for storage, charging stations and UPS DC links: single-pole, 1,500 V class, bidirectional.

    • C303: 500 A continuous, 5,000 A for 20 ms without welding
    • Ecosave, high-efficiency and precharge coil options
    • C305 and C330 extend to 1,500 A and 2,000 A for megawatt charging

    See the range

    Schaltbau C310 DC contactor
    02

    C310 and C320

    Single-pole contactors for higher voltage and current than the C300 tier.

    • C310: 1,500 V, 500 A, AC and DC
    • C320: 1,800 V insulation, 1,000 A continuous, 4,500 A for 100 ms
    • UL Recognized Component to UL 60947-4-1, file E116641

    See the range

    Schaltbau C800 series DC contactor
    03

    C800 family, on the vehicle

    The same bidirectional switching, built for the shock and vibration of a battery disconnect unit.

    • Rated to ISO 16750-3 shock and vibration profiles
    • C800: 1,500 V insulation, 500 A continuous, 6,000 A short-time
    • C801 reconfigures an 800 V pack to charge at a 400 V station

    See the range

    Schaltbau CP series high-voltage contactor
    04

    CP, CT and CF high-voltage contactors

    Double-break contactors to 3,000 V for large storage, heavy equipment and test benches, built to be serviced.

    • CT: 1,500 V or 3,000 V, 400 and 800 A, contact tips and arc chute replaceable
    • CP: frames to 2,000 A, arc chamber swaps without tools
    • CF: configurable from one to six poles

    See the range

    Also from Schaltbau: HV connectors to 1,000 V DC and 470 A, IP69K mated, over 10,000 mating cycles, with a switch that reports the plug is home. LV charging connectors to 500 A. The CPP compact precharge contactor to 1,500 V and 160 A. S8 snap-action switches with 10 million mechanical cycles and shock to 80 g, the same family as the mirror contact inside the contactors.

    Specs and datasheets at Schaltbau

    The engineering behind it

    Why it still breaks the bus late in its life
    DC has no zero crossingAn AC arc dies at the next zero. A DC arc has to be stretched and quenched by the contactor.
    Permanent-magnet blowoutThe arc is driven into an open arc chamber and extinguished, with no gas fill to age.
    Either direction, one deviceBidirectional switching for charge, discharge and regeneration.
    Wear you can seeOn serviceable families the contact set is the wear part, not the contactor.
    Ratings set at thermal currentPublished voltage is stated at maximum thermal current; ask about your actual V and I.
    State feedback built inMirror contacts to IEC 60947-4-1 Annex F tell the controller the real position.

    The long form: how to read a DC contactor datasheet, every rating explained

    Questions engineers ask us

    Straight answers on DC contactors
    Why can't an ordinary AC contactor break a DC circuit?

    An AC arc goes out on its own at the next current zero, many times a second. A DC bus never crosses zero, so the arc keeps burning until the contactor stretches and cools it. DC contactors are built to do that: Schaltbau uses permanent-magnet blowout to drive the arc into an open arc chamber and extinguish it.

    What should I specify for a DC contactor instead of cycle count?

    Specify breaking capacity and break life at your actual DC voltage and current. A headline cycle count is usually mechanical life, with almost no arc, and can be hundreds of times larger than the number of full-power interruptions the device survives. Ask for both life lines, and ask whether the contact set can be replaced in the field.

    Can one contactor switch current in both directions?

    Yes. The Schaltbau C303, C310 and C320 switch DC in either direction through one device, which a battery needs for charge, discharge and regeneration. On any contactor, check the break rating in the reverse direction as well as the forward one.

    Open-chamber or sealed gas-filled DC contactor?

    Sealed gas-filled contactors quench arcs well in a compact, sealed package. Open-chamber contactors with permanent-magnet blowout have no gas fill to age, and on serviceable families you can inspect the contacts and replace them instead of the whole device. Which is right depends on the enclosure, the duty and how long the equipment has to run.

    Are Schaltbau DC contactors UL listed?

    The Schaltbau C310 and C320 carry UL Recognized Component marks to UL 60947-4-1 under file E116641. We confirm the coverage for the specific part and rating against your application at quote time.

    Can a contactor switch a higher voltage than its datasheet rating?

    Published voltage ratings are stated at the contactor's maximum thermal current, and the real limit is heat at the contacts. At lower current there can be headroom, but it is a factory question for your exact voltage, current and duty, never an assumption.

    What contactor goes in a precharge circuit?

    The C303 is available with a precharge coil option for a main-plus-precharge topology. The compact CPP contactor switches up to 1,500 V and 160 A as the precharge partner to a larger main contactor.

    Who supports Schaltbau in Northern California and Nevada?

    Dynamic Measurement and Control Solutions is the Schaltbau representative for Northern California and Northern Nevada. Send the bus voltage, the current and what the contactor has to do, and we tell you whether Schaltbau fits and which series to look at.

    Where Schaltbau works

    Anywhere a DC bus has to be broken safely
    Energy, power and electrification systemsBattery storage, solar combiners and DC grids.Data centers and digital infrastructureIsolation on the 800 VDC bus and the battery behind it.Transportation, mobility and vehicle systemsCharging stations and on-vehicle battery disconnects.Heavy equipment, mobile machinery and outdoor systemsElectrified machines under shock and vibration.Semiconductor and test equipmentBattery and power test benches at high voltage.Robotics, robot cells and mobile robotsBattery disconnects for AGVs and mobile platforms.Industrial automation and production equipmentDC switching inside the machine and the panel.Building, facility and site systemsDC links in UPS and site storage.

    The rest of the power path

    Schaltbau switches the DC. These lines convert it, connect it and measure it.
    Premium PSUConverts the DC Schaltbau switches, up to the 800 VDC bus.Walther ElectricConnectors and distribution on the AC side.CelducSolid state relays for the smaller, high-cycle loads.SATECProve it: AC and DC metering on the same bus.

    Where it lands: the contactor that carries the DC bus and breaks it under load or on a fault: Power That Performs, stage 07 Switching the load on the design path.

    More on the arc: open-air blowout versus sealed gas-filled over the life of the machine. See every line in design order on the design path.

    Downloads with Schaltbau on them

    • Schaltbau at a glance, 1 page
    • Energy systems line card
    • Data center line card
    • Heavy equipment line card
    • Automated off-road vehicles line card
    • Semiconductor and test equipment line card

    Every Dynamic download

    Send us your voltage, current and duty

    The bus voltage, the continuous and fault current, the direction of current and what the contactor has to do. We come back with the series to look at and what to ask for on the datasheet. If the job needs something outside the Schaltbau range, we know someone who has it.

    Send us your voltage and current

    ×

    Send us your voltage, current and duty

    Answer what you can. Only email is required. We tell you whether Schaltbau fits and which series to look at.

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