Introduction: Renewable energy converters combine a main high-voltage DC power path with many lower-voltage auxiliary circuits, so the key distinction is where a 100A magnetic latching relay fits and where a main DC contactor remains necessary.
When a solar inverter or battery converter cabinet is specified, it is tempting to reach for the biggest numbers on a component listing and apply them everywhere. A specification sheet can make a 100A latching relay and renewable energy converters look like a direct main-power solution. That assumption can lead to a component being specified for a duty it was not intended to perform. The YC602 is a magnetic latching relay rated for 100A at 250VAC with a maximum switching voltage of 400VAC/110VDC. YongNeng Relay Manufacturer lists renewable energy converters as a published application area for the YC602, and that listing points to auxiliary circuits rather than the high-voltage DC main path. That distinction matters because engineers working with converter cabinets will notice when a component's role is overstated.
A renewable energy converter is not just one large power stage. Around the main conversion circuit sits a network of smaller control and support functions. Cooling fans need to turn on and off. Auxiliary power supplies need enable signals. Cabinet heaters, dehumidifiers, status indicators, and communication modules all draw power from somewhere. These are the loads that auxiliary switching handles. They are real, they matter to uptime, and they operate at voltages and currents well below the main DC bus. This is where a 100A latching relay fits naturally. The YC602's 100A 250VAC contact rating and 25,000VA maximum switching power give it enough headroom for many auxiliary distribution duties inside a converter cabinet, including load bank switching, auxiliary transformer control, and service disconnect functions. Its contact arrangement of 1A or 1B, silver alloy contacts, and ≤0.8mΩ contact resistance also help keep voltage drop low across the switched path. The accurate technical framing is auxiliary power management, not main power conversion. The published YC602 data lists renewable energy converters as an application area, but it does not specify a converter topology. That leaves room for reasonable interpretation without overreach. A three-phase string inverter, a central inverter, and a battery DC-DC converter all have auxiliary circuits. A latching relay could serve in any of them. What it does not do is switch the high-voltage DC bus that carries the main converted power. That job belongs to high-voltage DC contactors designed for arc suppression and DC isolation.
Thermal management is a quiet constraint in every converter design. Cabinets are often sealed or tightly filtered, and every watt of heat inside has to leave through a heat sink, an air conditioner, or a fan. A standard electromagnetic relay with a 3W coil adds heat continuously whenever it is energized. Multiple such relays in one cabinet turn into a measurable thermal load. That heat ages nearby components faster and forces the cooling system to work harder. A magnetic latching relay changes that equation because its coil is not the steady-state heat source anymore.
The YC602 uses a pulse to change state. A minimum pulse duration of 50ms at 70% of rated coil voltage is enough to set or release the contacts. After that pulse ends, a permanent magnet inside the relay holds the contacts in position. The coil is de-energized. No current flows through it. For a converter cabinet running in standby mode, this means the relay is not adding heat while it waits. That matters for renewable energy systems because they often sit in outdoor enclosures with limited cooling and wide ambient swings. The YC602's -40℃ to +85℃ operating range covers those conditions, and the pulse-held design keeps the thermal budget focused on the power stage rather than on control relays.
The YC602's maximum switching voltage is published as 400VAC/110VDC, and its maximum switching power is 25,000VA. These are product-specific conditions from the published data. In a converter auxiliary circuit, the actual voltage present at the relay terminals depends on where the designer places it. A 400VAC auxiliary feed on a large central inverter is possible. So is a 110VDC control bus. The published rating represents a ceiling under specified conditions, and a system review should confirm that the circuit's voltage, load type, and inrush characteristics fall within it. The 4,000VAC coil-to-contact dielectric strength and 1,800VAC contact-gap rating give the control side useful isolation from the switched side, which is relevant when a PLC or low-voltage control board is coordinating the relay.
The most common mix-up in renewable energy converter designs is treating a latching relay as a smaller, cheaper substitute for a main DC contactor. The two devices look similar at a glance, and both can be rated at 100A or more. But their jobs are different. A main-circuit high-voltage DC contactor in a converter or battery system has to break DC arcs, maintain isolation under fault conditions, and meet specific DC switching requirements. The YC602's published data does not state high-voltage DC isolation as a capability. Its 110VDC maximum switching voltage is far below the DC bus voltages found in many commercial and utility-scale converters. Expecting it to interrupt a 600V or 1,000V DC main path would push it outside anything the published specifications support. Auxiliary circuits, by contrast, are where the YC602's profile lines up well. These circuits carry control power, fan loads, and service functions. They rarely see the full main DC bus, and they often benefit from a relay that holds state without continuous coil current. That distinction keeps the technical picture sound and gives engineers a realistic view of how the component fits into a converter cabinet.
A 100A magnetic latching relay like the YC602 is a useful component in renewable energy converter auxiliary circuits because it combines high current capacity with pulse-held contacts that do not add continuous coil heat. Its published 400VAC/110VDC and 25,000VA ratings support auxiliary switching duties when the circuit conditions are reviewed against them. It is not a main-circuit high-voltage DC contactor replacement, and describing it that way would misstate its role. The clearer picture is about auxiliary power management, thermal efficiency in enclosed cabinets, and a component that does its job quietly in the background of a converter system. For a specific converter cabinet, confirming the auxiliary voltage, load type, and coil drive through the manufacturer's application engineering channel is the practical next step before final selection.
A：Main-circuit DC contactors are designed for high-voltage DC arc interruption and isolation, while the YC602 is positioned for auxiliary control and support circuits with a published maximum switching voltage of 110VDC. Use a properly rated DC contactor for the main DC power path and a latching relay for auxiliary switching duties.
A：A latching relay changes state with a short pulse, then a permanent magnet holds the contacts without coil current. Unlike a standard relay that stays energized continuously, the YC602 does not add steady coil heat during standby. In a sealed or poorly ventilated cabinet, removing that continuous heat source lowers the overall thermal load and reduces stress on other components.
A：It defines the published maximum switching voltage as 400VAC or 110VDC under the stated conditions. Auxiliary circuits in a converter cabinet that operate within those levels can be reviewed against the YC602 data, with actual circuit voltage, load type, and inrush checked before selection.
NXP Semiconductors: Smart Energy and Prepayment Disconnect Relays
