When selecting a three-phase power regulator, many customers focus first on total power—asking, "What size do I need?" based on the equipment's actual load wattage. While this approach isn't wrong, power rating alone isn't enough; we also need to consider voltage, current per phase, load type, the temperature controller's output signal, and the electrical cabinet's heat dissipation conditions.

First, distinguish between single-phase and three-phase systems. Use a single-phase power regulator for 220V single-phase heating elements, but for 380V three-phase heating equipment—such as ovens, electric furnaces, heat treatment furnaces, or drying equipment—we must use a three-phase power regulator. Even if the total power is low, if the load is wired in a three-phase configuration, we cannot simply choose a single-phase unit for convenience; you must calculate the current based on three-phase requirements. The key factor is the current per phase. For instance, with a 380V, 15kW three-phase heating unit in Star configuration, the theoretical current is approximately 15 ÷ 1.732 ÷ 0.38 ≈ 22.8A. I recall an oven manufacturer who calculated 22A and selected a 25A regulator. However, during the summer, high temperatures inside the electrical cabinet caused the unit to frequently trigger overheat protection during continuous daily operation. After Maxwell recalculated the requirements and recommended upgrading to a 35A model—providing a safety margin—the issue was immediately resolved. Therefore, do not select a regulator based on the bare minimum current; consider voltage fluctuations, phase balance, and on-site operating conditions, and choose the next size up.

Furthermore, you must verify the output signal of the temperature controller. Common signals include SSR (pulse) signals, 4-20mA, 0-10V, 0-5V, and manual potentiometer inputs. Confirm this clearly before purchasing to avoid compatibility issues. For example, one customer had a temperature controller with a 4-20mA output but purchased a regulator that only supported SSR triggering, rendering it completely unusable. The problem was only solved after switching to a Hequan model that supported analog inputs. Simply asking for the temperature controller's model number can save a lot of trouble.

Finally, do not overlook heat dissipation in the electrical cabinet. Power regulators generate heat themselves. If the cabinet space is cramped, lacks fans, is located near the furnace body, and operates at full load all day, it is even more critical to avoid selecting a unit that operates right at its limit. It is recommended to install a fan inside the cabinet, ensure adequate clearance around the heatsink, keep the unit away from high-temperature sources, and ensure cable terminals are securely tightened. Many failures are not caused by poor product quality, but rather by overheating due to cramped installation or inadequate heat dissipation.

In short, when selecting a three-phase power regulator, do not simply ask, "What size matches a specific kilowatt rating?" You must consider voltage, total power, current per phase, temperature controller signals, cabinet heat dissipation conditions, and whether the equipment operates at full load for extended periods. If you are working on ovens, electric furnaces, heat treatment furnaces, or drying equipment and are unsure about the configuration, simply send us the power rating, voltage, wiring method, temperature controller model, and a photo of the electrical cabinet; Hequan will calculate the current and recommend a suitable solution.