How Much Power Should a 3-Phase SCR Regulator Have for Heater Control?

Published: December 7, 2024

When selecting a 3-phase SCR (Silicon Controlled Rectifier) power controller, the most important factor is matching the controller's specifications to your heating system's power requirements. Whether you're using a 380V, 220V, or 440V power supply, proper selection ensures efficient heating performance and longevity of your equipment.

Choosing an SCR Power Controller for a 380V Power Supply

1. Determine the Heater’s Power

To select the correct SCR power controller, start by calculating the heater’s power. Divide the heater's rated power by a safety factor of 0.8. The SCR controller’s power rating should be at least this value.

2. If Only Current is Known

In cases where only the current is available, use the formula:

P = √3 * U * I

Where P is the power, U is the voltage (380V in this case), and I is the current. Once the power is calculated, proceed with step 1.

Choosing an SCR Power Controller for 220V or 440V Power Supply

For SCR controllers operating with 220V or 440V, the selection process is similar, with the primary difference being the adjustment for voltage differences.

3. Adjusting for 220V or 440V

The same power controller has the same permissible heat generation under different load power supplies, that is, its permissible passing current is the same. According to this principle, 220V and 440V selection can be converted to 380V selection:

Heater Power ÷ Voltage × 380V ÷ 0.8 = Minimum SCR Power Controller Rating

By following this formula, please ensure that the result value is not bigger than the controller's power.

Quick Reference Table for SCR Power Controller Selection

Here’s a quick guide to choosing the right SCR power controller based on the heater's voltage and power:

220V Heater Power (kW)	380V Heater Power (kW)	440V Heater Power (kW)	SCR Power Controller Selection
0 < P ≤ 7.41	0 < P ≤ 12.8	0 < P ≤ 14.82	APR3H16G
7.41 < P ≤ 10.19	12.8 < P ≤ 17.6	14.82 < P ≤ 20.38	APR3H22G
10.19 < P ≤ 13.89	17.6 < P ≤ 24	20.38 < P ≤ 27.79	APR3H30G
13.89 < P ≤ 18.53	24 < P ≤ 32	27.79 < P ≤ 37.05	APR3H40G
18.53 < P ≤ 23.16	32 < P ≤ 40	37.05 < P ≤ 46.32	APR3H50G
23.16 < P ≤ 27.79	40 < P ≤ 48	46.32 < P ≤ 55.58	APR3H60G
27.79 < P ≤ 32.42	48 < P ≤ 56	55.58 < P ≤ 64.84	APR3H70G
32.42 < P ≤ 37.05	56 < P ≤ 64	64.84 < P ≤ 74.11	APR3H80G
37.05 < P ≤ 41.68	64 < P ≤ 72	74.11 < P ≤ 83.37	APR3H90G
41.68 < P ≤ 46.32	72 < P ≤ 80	83.37 < P ≤ 92.63	APR3H100G
46.32 < P ≤ 50.95	80 < P ≤ 88	92.63 < P ≤ 101.89	APR3H110G
50.95 < P ≤ 61.14	88 < P ≤ 105.6	101.89 < P ≤ 122.27	APR3H132G
61.14 < P ≤ 69.47	105.6 < P ≤ 120	122.27 < P ≤ 138.95	APR3H150G
69.47 < P ≤ 74.11	120 < P ≤ 128	138.95 < P ≤ 148.21	APR3H160G
74.11 < P ≤ 81.05	128 < P ≤ 140	148.21 < P ≤ 162.11	APR3H175G
81.05 < P ≤ 92.63	140 < P ≤ 160	162.11 < P ≤ 185.26	APR3H200G
92.63 < P ≤ 101.89	160 < P ≤ 176	185.26 < P ≤ 203.79	APR3H220G
101.89 < P ≤ 115.79	176 < P ≤ 200	203.79 < P ≤ 231.58	APR3H250G
115.79 < P ≤ 129.68	200 < P ≤ 224	231.58 < P ≤ 259.37	APR3H280G
129.68 < P ≤ 138.95	224 < P ≤ 240	259.37 < P ≤ 277.89	APR3H300G
138.95 < P ≤ 148.21	240 < P ≤ 256	277.89 < P ≤ 296.42	APR3H320G
148.21 < P ≤ 162.11	256 < P ≤ 280	296.42 < P ≤ 324.21	APR3H350G
162.11 < P ≤ 185.26	280 < P ≤ 320	324.21 < P ≤ 370.53	APR3H400G
185.26 < P ≤ 208.42	320 < P ≤ 360	370.53 < P ≤ 416.84	APR3H450G
208.42 < P ≤ 231.58	360 < P ≤ 400	416.84 < P ≤ 463.16	APR3H500G
231.58 < P ≤ 254.74	400 < P ≤ 440	463.16 < P ≤ 509.47	APR3H600G
254.74 < P ≤ 277.89	440 < P ≤ 480	509.47 < P ≤ 555.79	APR3H600G
277.89 < P ≤ 291.79	480 < P ≤ 504	555.79 < P ≤ 583.58	APR3H630G

Conclusion

Choosing the right SCR power controller is crucial for the optimal performance of your heating system. By following the power calculations and selecting the appropriate controller based on the heater’s power and voltage, you ensure that the system operates efficiently and reliably. The provided table is a quick and effective guide to simplify the selection process. If you need further assistance, don't hesitate to reach out to us for personalized advice.