Why do electric actuators always show over torque？

  電動(dòng)執(zhí)行器為什么總顯示過(guò)力矩？如何安全使用電動(dòng)執(zhí)行器呢？中英合資天蝶閥門(mén)來(lái)給大家詳細(xì)講解。

  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.

  當(dāng)電動(dòng)執(zhí)行器的規(guī)格確定之后，其控制轉(zhuǎn)矩也確定了。當(dāng)其在預(yù)先確定的時(shí)間內(nèi)運(yùn)行時(shí)，電機(jī)一般不會(huì)超負(fù)荷。但如出現(xiàn)下列情況便可使其超負(fù)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.電源電壓低，得不到所需的轉(zhuǎn)矩，使電機(jī)停止轉(zhuǎn)動(dòng)。

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

  2.錯(cuò)誤地調(diào)定了轉(zhuǎn)矩限制機(jī)構(gòu)，使其大于停止的轉(zhuǎn)矩，而造成連續(xù)產(chǎn)生過(guò)大的轉(zhuǎn)矩，使電機(jī)停止轉(zhuǎn)動(dòng)。

  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.如點(diǎn)動(dòng)那樣斷續(xù)使用，產(chǎn)生的熱量積蓄起來(lái)，超過(guò)了電機(jī)的容許溫升值。

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

  4.因某種原因轉(zhuǎn)矩限制機(jī)構(gòu)電路發(fā)生故障，使轉(zhuǎn)矩過(guò)大。

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

  5.使用環(huán)境溫度過(guò)高，相對(duì)地使電機(jī)的熱容量下降。

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

  以上是出現(xiàn)超負(fù)荷的一些原因，對(duì)于這些原因產(chǎn)生的電機(jī)過(guò)熱現(xiàn)象應(yīng)預(yù)先考慮到，并采取措施，防止過(guò)熱。
  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.

  過(guò)去對(duì)電動(dòng)執(zhí)行器電機(jī)進(jìn)行保護(hù)的辦法是使用熔斷器、過(guò)流繼電器、熱繼電器、恒溫器等，但這些辦法也都各有利弊，對(duì)于電動(dòng)裝置這種變負(fù)荷的設(shè)備，可靠的保護(hù)辦法是沒(méi)有的。因此必須采取各種方法組合的方式。但由于每臺(tái)電動(dòng)裝置的負(fù)荷情況不同，難以提出一個(gè)統(tǒng)一的辦法。但概括多數(shù)情況，也可以從中找到共同點(diǎn)。

  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.

  采取的過(guò)負(fù)荷保護(hù)方式，歸納為兩種：

  There are two types of overloading protection:

  1．對(duì)電動(dòng)執(zhí)行器電機(jī)輸入電流的增減進(jìn)行判斷；

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

  2．對(duì)電機(jī)本身發(fā)熱進(jìn)行判斷。

  2. Judge the heating of the motor itself.

  上述兩種方式，無(wú)論那種都要考慮電機(jī)熱容量給定的時(shí)間余量。如果用單一方式使之與電機(jī)的熱容量特性一致是困難的。所以應(yīng)選擇根據(jù)過(guò)負(fù)荷的原因能可靠的動(dòng)作的方法——組合復(fù)合方式，以實(shí)現(xiàn)全面的過(guò)負(fù)荷保護(hù)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.

  中英合資天蝶閥門(mén)生產(chǎn)的電動(dòng)執(zhí)行器電機(jī)，因其在繞組中埋入了與電機(jī)絕緣等級(jí)一致的恒溫器，當(dāng)?shù)竭_(dá)額定溫度時(shí)，電機(jī)控制回路便會(huì)切斷。恒溫器本身熱容量是較小的，而且其*特性是由電機(jī)的熱容量特性決定的，因此這是一個(gè)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. 

  電動(dòng)執(zhí)行器過(guò)負(fù)荷的基本保護(hù)方法是：

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

  1.對(duì)電機(jī)連續(xù)運(yùn)轉(zhuǎn)或點(diǎn)動(dòng)操作的過(guò)負(fù)荷保護(hù)采用恒溫器；

  1. Use a thermostat for over-load protection of the continuous operation or point operation of the motor;
  2.對(duì)電機(jī)堵轉(zhuǎn)的保護(hù)采用熱繼電器；

  2. Use thermal relay to protect the motor;
  3.對(duì)短路事故采用熔斷器或過(guò)流繼電器。

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