Distinguish between AC spot welder and DC spot welder

Spot welding machines can be classified into DC and AC according to the current. Many people don't know the distinction between DC spot welders and AC spot welders. Do you want to know how to distinguish them? Here are four ways to distinguish them:

1. Welding quality of spot welding machine

The adjustment period of the AC spot welding machine is long. For the 50Hz power grid, the welding time adjustment resolution is 20ms. The time adjustment resolution of the inverter DC spot welding machine can reach 0.25ms (4kHz inverter frequency), and the control accuracy is high. The response speed of the feedback control of the inverter spot welding machine is obviously accelerated, and the output stability is good.

Due to the influence of excessive current, the thermal efficiency of AC spot welding machine is low, and thyristor is used to adjust the current. When the current percentage is too small, the zero-crossing time is long, and the impact is greater. The output current of the DC spot welding machine is pulsating DC, and it is a continuous DC output under the action of the loop inductance, with high thermal efficiency, and the welding heat input of the spot welding machine is stable.

2. Welding speed of spot welding machine

Due to the influence of the current zero-crossing, the heating time of the AC spot welding machine is relatively long. The inverter resistance spot welding machine is DC output, the heating is concentrated, and the welding time is shortened.

3. Energy saving effect of spot welding machine

The AC spot welding machine works at 50Hz, the transformer loss is large, the power factor of the welding machine is low, and the loop loss is large. The inverter welding machine transformer works at a higher frequency (1-4kHz), the loss is very small, the DC output improves the power factor, and the energy saving effect is obvious.

4. Volume and weight of spot welding machine equipment

The transformer core of the AC spot welding machine is larger, and the equipment is bulkier under the same power condition. The transformer of the DC resistance spot welding machine is greatly reduced, and the equipment is lighter.