Inside a holiday kitchen: the engineering behind a power relay
During China's National Day holiday, ovens and rice cookers help prepare family meals. In an appliance using an electromagnetic relay, a quiet click may mark another opening or closing of its contacts. Hidden on the control board, the component connects and disconnects the load.
For appliance designers outside China, comparing Hongfa's HF115F with Panasonic's LZ series offers a practical view of the work behind that familiar action. Their published ratings also show which details matter when evaluating a Chinese supplier for an existing or new design.
A kitchen load tests more than switching operation
The appliance controller measures temperature and executes its program. A driver energizes the relay coil, and magnetic force moves the contacts. That action switches the heater's load circuit while maintaining electrical isolation between coil and contacts. The complete appliance still requires its own temperature protection and other safety functions.
Once closed, the contacts must tolerate current-induced heating. When they open, they face arcing. Motors, heaters and power supplies with input capacitors impose different demands, including starting current, steady-state temperature rise and turn-on surge.
A 16A marking is therefore only the beginning of a selection exercise. The relevant rating may apply to AC or DC, a resistive or inductive load, and a specified ambient temperature. Space constraints and nearby heat sources can make operation inside an appliance considerably more demanding than a simple bench test.
Figure 1. Simplified heating-control functions, not a specific appliance BOM. Temperature protection, fusing and power-supply details are omitted.
HF115F specifications expose the design trade-offs
Hongfa's HF115F is a miniature power relay. Its 2025 Rev.1.00 datasheet lists a height of 15.7mm, coil power of approximately 400mW and a 16A, 250VAC resistive-load rating for relevant single-pole variants. Height affects enclosure clearance; coil power affects the driver supply and internal heating.
The family includes different contact configurations and materials. The datasheet lists variants using silver-nickel and silver-tin-oxide contacts, with certified loads and temperature conditions that vary by entry. The complete ordering code matters even within the same relay family. Conductivity, arc resistance and resistance to contact welding have to work with contact force, separation and the operating mechanism. A suffix on the purchasing specification may identify one of those differences.
HF115F's listed mechanical endurance is 10 million operations. For its 1H3B specification, electrical endurance is 100,000 operations at a 16A, 250VAC resistive load and room temperature, with one second on and nine seconds off. Mechanical cycling and switching an energized load impose different stresses. Neither count can be converted directly into years of appliance service without considering the actual load, temperature and operating frequency.
Figure 2. HF115F example from Hongfa's datasheet. The pictured unit is an 8A variant; the 16A data in the text apply to a different contact configuration.
Panasonic provides a comparison under defined conditions
Panasonic's February 2026 electromechanical-relay selection guide lists the LZ series in a similar power range. Relevant specifications include a 16A, 250VAC resistive-load rating, 15.7mm height and 400mW coil power. Both vendors also list an initial coil-to-contact dielectric withstand test of 5000V AC for one minute.
Figure 3. Panasonic's official LZ product image. Series specifications were checked against its February 2026 selection guide.
Ambient temperature reveals a distinction. The reviewed HF115F datasheet lists -40°C to 85°C. Panasonic separates Class B and Class F versions, whose upper ambient limits are 85°C and 105°C respectively. A hotter control-board location makes this distinction relevant, subject to the specific part's load and drive conditions. Dielectric withstand is a test rating under defined conditions, not the normal operating voltage that may continuously be applied.
Similar headline specifications establish a basis for evaluation. Replacement still requires checks of contact form, pin layout, pickup and release conditions, and certification scope. Endurance comparisons require matching load, temperature and switching sequence. The materials reviewed do not include a common-condition endurance test of the two products, so they do not establish which lasts longer.
Figure 4. Series capability comparison compiled from the two vendors' documents. Variants differ; this table does not establish drop-in interchangeability.
Production consistency starts with tooling and parts
A compact relay must allocate space to the coil, magnetic circuit, contacts and insulation. Consistent production then depends on controlling variation in those parts and their assembly. Contact position, spring geometry and assembly dimensions can all affect operation. Tooling, component processing and inspection remain important after the drawing is complete.
Hongfa's 2026 interim report describes an industrial chain covering molds, precision parts, and the design and manufacture of automated production lines. During the reporting period, it reported nearly RMB1 billion in technical-upgrade investment, 22 newly commissioned flexible or automated lines, and 80 sets of high-precision upstream component equipment. These are company-wide figures, not spending attributable solely to HF115F.
The relevant product outcome is how that manufacturing capability supports dimensional control, temperature rise, endurance and consistency between batches. Appliance boards may need to become smaller, but thermal and insulation requirements still have to be met. Lower drive power also has to preserve dependable operation. Materials, mechanical design and manufacturing work together on each improvement.
When a holiday meal reaches the table, the relay may have completed another cycle unnoticed. For component engineers and buyers, the useful achievement is a device that repeatedly performs its specified task under the agreed operating conditions. The National Day kitchen provides a familiar setting for work that applies to appliance manufacturing worldwide.
Based on published manufacturer material. This comparison does not establish direct interchangeability or constitute a purchasing recommendation. Validate the complete part number under the appliance's operating conditions.
