IN Brief:
- HVC28 has a 1,000 V operating limit and a 16 kA short-circuit withstand rating for 5 ms.
- HVC29 is specified to 1,500 V, with a separate 6 kA short-circuit withstand rating for 5 ms.
- Both series offer polarity-free terminals, 12 V or 24 V coils and optional mechanically linked mirror contacts.
TDK has introduced HVC28 and HVC29 gas-filled DC contactors for traction batteries, charging equipment and industrial power systems. The HVC28 is rated for operating voltages up to 1,000 V and the HVC29 for up to 1,500 V. Both series are offered with 300 A, 400 A, 500 A and 600 A continuous current ratings, allowing equipment manufacturers to select a current class within either voltage family.
TDK specifies short-circuit withstand of 16 kA for 5 ms for HVC28, compared with 6 kA for 5 ms for HVC29. These are time-limited withstand ratings: the contacts must survive a defined fault current while other protective equipment responds. Continuous current, fault withstand and interruption capability are separately specified when coordinating a DC isolation system. A higher operating voltage rating therefore does not establish equivalent performance under the same prospective short circuit conditions, particularly when battery or converter capacity differs between installations.
HVC28 also carries a single maximum cut-off specification of 1,600 A at 1,000 V under stated resistive load conditions. That test condition matters because opening an energised DC circuit can produce a sustained arc across separating contacts. Direct current lacks the periodic current zero crossing present in an AC circuit, so the contact geometry and the arc chamber must control interruption. The single operation figure cannot be transferred to every inductive or capacitive switching duty.
Each series uses a gas-filled ceramic arc chamber and polarity-free main terminals. The chamber supports arc control when the contacts separate, while the bidirectional terminals accommodate systems in which current can flow in either direction, such as battery charging and discharging. Actual switching duty must still be coordinated with fuse selection, circuit protection and the electrical behaviour of the connected energy storage or power converter.
TDK targets the HVC28 principally at battery disconnect units, high-voltage junction boxes, traction batteries, commercial vehicles and fast-charging installations. The 1,500 V HVC29 is oriented towards stationary energy storage, uninterruptible power supplies and solid-state transformers. The company also identifies developing 800 V DC architectures in AI data centres as an application area, where distribution and isolation equipment must accommodate fault energy as well as normal load current.
An optional normally closed mirror contact provides a mechanically linked auxiliary indication of the main contact state. TDK identifies the function with IEC 60947-4-1, enabling a monitoring circuit to compare a commanded change with the resulting contact position. The auxiliary signal provides an additional diagnostic input for system controls; protective logic, insulation monitoring and the selection of upstream disconnect devices remain part of the wider safety architecture.
The contactors use a single coil with either a 12 V or 24 V nominal supply, consuming 6 W at the specified voltage. Both share dimensions of 95.5 × 96 × 49 mm and an operating temperature range of −40°C to +85°C. HVC28 weighs approximately 640 g, against about 630 g for HVC29. Common dimensions can simplify mechanical integration where a cabinet or battery enclosure must accommodate alternative voltage classes.
Busbars, cable terminations and mounting arrangements must carry the selected normal current, while the coil supply and auxiliary feedback need separate control connections. Coil energisation is a control command, whereas the mirror contact supplies information about mechanical state. Designs with precharge circuits or multiple disconnect devices need coordinated sequences to avoid exposing an individual contactor to an inappropriate load at the instant of switching.
TDK reports CE and UKCA compliance and certification to UL 60947-4-1, with CCC certification pending. Component selection should therefore match the published variant ratings to operating voltage, available fault current, load type, ambient temperature and required approvals. HVC29 extends the voltage envelope but has a lower short-circuit withstand figure than HVC28, a consequential difference for charging, energy storage and high voltage distribution equipment.
