电动执行器为什么总显示过力矩？

Why do electric actuators always show over torque？

  电动执行器为什么总显示过力矩？如何安全使用电动执行器呢？中英合资天蝶阀门来给大家详细讲解。

  Why do electric actuators always show over torque？How to use electric actuator safely?The Sino-British joint venture Tandy Valve will explain it to you in detail.

  当电动执行器的规格确定之后，其控制转矩也确定了。当其在预先确定的时间内运行时，电机一般不会超负荷。但如出现下列情况便可使其超负荷：

  When the specification of the electric actuator is determined, the control torque is also determined.When it runs in a predetermined period of time, the motor is generally not overloaded. However, it will be overloaded if : 

  1.电源电压低，得不到所需的转矩，使电机停止转动。

  1. Low supply voltage, can not get the required torque, so that the motor stops turning.

  2.错误地调定了转矩限制机构，使其大于停止的转矩，而造成连续产生过大的转矩，使电机停止转动。

  2. The torque limiting mechanism is set incorrectly so that it is greater than the stopping torque, resulting in the continuous generation of excessive torque, so that the motor stops turning.

  3.如点动那样断续使用，产生的热量积蓄起来，超过了电机的容许温升值。

  3. If the intermittent use of the point move, the heat generated by the savings, exceeding the allowable temperature appreciation of the motor. 

  4.因某种原因转矩限制机构电路发生故障，使转矩过大。

  4.For some reason, the circuit of torque limiting mechanism breaks down and the torque is too large.

  5.使用环境温度过高，相对地使电机的热容量下降。

  5. The use of ambient temperature is too high, relative to the heat capacity of the motor decreased. 

  以上是出现超负荷的一些原因，对于这些原因产生的电机过热现象应预先考虑到，并采取措施，防止过热。
  These are some of the causes of overload, for these reasons the phenomenon of motor overheating should be considered in advance, and take measures.Prevent overheating.

  过去对电动执行器电机进行保护的办法是使用熔断器、过流继电器、热继电器、恒温器等，但这些办法也都各有利弊，对于电动装置这种变负荷的设备，可靠的保护办法是没有的。因此必须采取各种方法组合的方式。但由于每台电动装置的负荷情况不同，难以提出一个统一的办法。但概括多数情况，也可以从中找到共同点。

  In the past, the electric motor for electric actuators was protected by fuses, overcurrent relays, thermal relays, thermostats, etc, But these methods also have their advantages and disadvantages, for the electric device such as the variable load equipment, absolutely reliable protection method is not available. It is therefore necessary to adopt a combination of approaches. However, due to the different load conditions of each electric device, it is difficult to propose a unified approach. But in most cases, common ground can also be found.

  采取的过负荷保护方式，归纳为两种：

  There are two types of overloading protection:

  1．对电动执行器电机输入电流的增减进行判断；

  1. Judging the increase or decrease of the input current of the motor in the valve electric device;

  2．对电机本身发热进行判断。

  2. Judge the heating of the motor itself.

  上述两种方式，无论那种都要考虑电机热容量给定的时间余量。如果用单一方式使之与电机的热容量特性一致是困难的。所以应选择根据过负荷的原因能可靠的动作的方法——组合复合方式，以实现全面的过负荷保护作用。

  The above two methods, regardless of the kind of motor heat capacity should be considered a given time margin. It is difficult to match the heat capacity characteristics of the motor in a single way. So should choose according to the reason of overload can reliable action method-combination compound way, in order to realize the comprehensive overload protection effect.

  中英合资天蝶阀门生产的电动执行器电机，因其在绕组中埋入了与电机绝缘等级一致的恒温器，当到达额定温度时，电机控制回路便会切断。恒温器本身热容量是较小的，而且其*特性是由电机的热容量特性决定的，因此这是一个可靠的方法。

  The special motor for electric actuator of the Sino-British joint venture Tandy Valve, because it has a thermostat embedded in the winding, which has the same insulation level as the motor, reaches the rated temperature.The motor control circuit will be cut off. The thermostat itself has a smaller heat capacity, and its time-limited characteristic is determined by the heat capacity characteristics of the motor, so this is a reliable method. 

  电动执行器过负荷的基本保护方法是：

  The basic protection methods for overload of valve electric devices are:

  1.对电机连续运转或点动操作的过负荷保护采用恒温器；

  1. Use a thermostat for over-load protection of the continuous operation or point operation of the motor;
  2.对电机堵转的保护采用热继电器；

  2. Use thermal relay to protect the motor;
  3.对短路事故采用熔断器或过流继电器。

  3. Use fuses or overcurrent relays for short-circuit incidents.