三相恒功率电热带和单相恒功率电热带的原理基本相同，不同之处是单相采用单相供电，三相带采用三相三角型供电，三相带除有单相电热带的特点外，特别适用于长距离、大管径管道的伴热和保温，可用于工厂一区、二区的爆炸性气体混合物T3组场合。

The feature of three phase cable is similar to that of single phase cable. The difference is that supply of the power is single-phase or three-phase. Three-phase heating cable owns the characteristic of single-phase heating cable, meanwhile It is specially applied in heating and temperature-maintenance for long-distance and big-diameter pipe. It is suitable to be used in ordinary and hazlo c areas.

三根平行的绝缘铜芯线为电源母线，在内护套绝缘层外缠绕电热丝，并将该电热丝每隔一定距离（即“发热节长”）分别依次与电源母线AB-BC-AC-AB……反复循环连接，在每二相间型成连续并联电阻。当母线通以三相电后，各并联电阻同时发热，而型成一条连续三相供电的加热带。

The tree parallel bus wries supply voitage a long the entire length of the heating cabe.A resistance wire heating element is spirally wraped around inner insulation contacting alternate bus wire(AB-BC-AC-AB……)at specific intervals forming heating zone.

产品特点 Production characteristic

FDP3-J3 型三相电热带除具有和FDP2型单相电热带相同的特点以外，还有以下优点：

1.三相电热带的*大允许使用长度高于单相电热带。

2.在大规模应用电热带的场合，能均衡电网负载。

3.三相电热带由于采用三根芯线，使电热带更趋遍平，降低了表面发热负符，增加对管道的热传导面积，提高了电热带的热传输效率及*高维持温度。

Compared to single-phase heating cable (FDP2), three-phase heating cable (FDP3) has the characteristics FDP2 has, it also has below advantages:

a. The max allowed length of three-phase heating cable is greater than that of single-phase heating cable.

b. It helps to relieve the electricity load in large-scale heating cable applicable net.

c. Due to three bus wires are in the FDP3, The heating cable is more flat and increase transfer heat areas and energy efficiency. Strengthen range is that ordinary rang add a oversheath and high strength mechanical and corrosive-proof feature.

■ 应用场合Applications

FDP3 型三相恒功率电热带与FDP2型单相恒功率电热带一样，能用于解决管道和阀门等的防冻和保温。但是，当在长距离、大口径管道进行伴热保温时，采用三相带比单相带更经济、更合理、更能显示使用三相带的优越型。

FDP3 three-phase constant watt heating cable provides frozen-prevention and temperature-maintenance of pipelines and valves which is same for FDP2 single-phase constant watt heating cable. However, when applied to long-distance and big-diameter pipes, using of three-phase heating cable is more economic and reasonable and showing more advantage.