HONEYWELL CC-TAIX01工控備件機(jī)器人模塊
熱極限汽車壽命的主要敵人之一是熱量。當(dāng)指定電機(jī)時(shí)，買方應(yīng)告知制造商負(fù)載條件和占空比，以及環(huán)境和驅(qū)動(dòng)負(fù)載的其他相關(guān)信息，如啟動(dòng)扭矩等。然后，制造商應(yīng)提供庫(kù)存電機(jī)或制造在這些條件下應(yīng)具有合理壽命的電機(jī)。電機(jī)熱極限由定子和轉(zhuǎn)子的設(shè)計(jì)決定。電機(jī)有三種運(yùn)行模式：鎖定轉(zhuǎn)子或失速（當(dāng)轉(zhuǎn)子未轉(zhuǎn)動(dòng)時(shí)）、加速（當(dāng)轉(zhuǎn)子達(dá)到速度時(shí)）和運(yùn)行（當(dāng)轉(zhuǎn)子以接近同步速度轉(zhuǎn)動(dòng)時(shí)）。在每種情況下，電機(jī)都會(huì)以非常不同的方式發(fā)熱。通常，在電機(jī)啟動(dòng)、鎖定轉(zhuǎn)子和加速條件下，電機(jī)受到轉(zhuǎn)子限制。也就是說(shuō)，轉(zhuǎn)子將在定子之前接近其熱極限。在鎖定轉(zhuǎn)子條件下，在轉(zhuǎn)子中感應(yīng)出線頻率為50或60 Hz的電壓。該電壓導(dǎo)致電流在轉(zhuǎn)子中流動(dòng)，也以線頻率流動(dòng)，產(chǎn)生的熱量（I2R）是有效轉(zhuǎn)子電阻的函數(shù)。在50或60 Hz時(shí)，轉(zhuǎn)子籠的電抗導(dǎo)致電流在轉(zhuǎn)子棒的外緣流動(dòng)。因此，轉(zhuǎn)子的有效電阻在鎖定轉(zhuǎn)子狀態(tài)下達(dá)到最大值，轉(zhuǎn)子加熱也是如此。當(dāng)電機(jī)以額定速度運(yùn)行時(shí)，轉(zhuǎn)子中感應(yīng)的電壓處于低頻（約1Hz），因此，轉(zhuǎn)子的有效電阻顯著降低。在運(yùn)行過(guò)載期間，電機(jī)熱極限通常由定子參數(shù)決定。某些特殊電機(jī)可能全定子或全轉(zhuǎn)子受限。在加速過(guò)程中，電機(jī)滑動(dòng)的動(dòng)態(tài)特性決定了轉(zhuǎn)子阻抗也是動(dòng)態(tài)的，需要第三個(gè)過(guò)載熱極限特性。下圖顯示了典型的熱極限曲線。顯示了80%電壓下高慣性負(fù)載的電機(jī)啟動(dòng)特性。如果電機(jī)啟動(dòng)更快，則不需要熱極限曲線的明顯特征，運(yùn)行過(guò)載曲線將與鎖定轉(zhuǎn)子安全失速時(shí)間相結(jié)合，以產(chǎn)生單個(gè)過(guò)載曲線。電機(jī)制造商應(yīng)為其銷售的任何電機(jī)提供安全失速時(shí)間或熱極限曲線。為了對(duì)469進(jìn)行最大程度的保護(hù)編程，當(dāng)電機(jī)招標(biāo)時(shí)，有必要詢問(wèn)這些項(xiàng)目。這些熱限值旨在用作指南，其定義并不總是精確的。當(dāng)電機(jī)運(yùn)行超過(guò)熱極限時(shí)，電機(jī)絕緣層不會(huì)立即熔化。相反，絕緣退化的速度已經(jīng)達(dá)到了這樣的程度：如果電機(jī)在這種條件下繼續(xù)運(yùn)行，其壽命將大大縮短。469的主要保護(hù)功能是熱模型。它由五個(gè)關(guān)鍵要素組成：過(guò)載曲線和過(guò)載拾取水平、電機(jī)運(yùn)行時(shí)電機(jī)電流的不平衡偏置、電機(jī)冷卻時(shí)間常數(shù)以及基于熱/冷電機(jī)信息和測(cè)量定子溫度的熱模型偏置。這些元素中的每一個(gè)都將在后面的章節(jié)中詳細(xì)描述。469將定子和轉(zhuǎn)子加熱集成到一個(gè)模型中。電機(jī)加熱反映在A1 STATUS？Motor STATUS？？Motor THERMAL CAPITAL USED實(shí)際值寄存器中。如果電機(jī)長(zhǎng)時(shí)間停止，則電機(jī)將處于環(huán)境溫度
THERMAL LIMITS One of the principle enemies of motor life is heat. When a motor is specified, the purchaser communicates to the manufacturer what the loading conditions and duty cycle will be, as well as, environment and other pertinent information about the driven load such as starting torque, etc. The manufacturer then provides a stock motor or builds a motor that should have a reasonable life under those conditions. Motor thermal limits are dictated by the design of both the stator and the rotor. Motors have three modes of operation: locked rotor or stall (when the rotor is not turning), acceleration (when the rotor is coming up to speed), and running (when the rotor turns at near synchronous speed). Heating occurs in the motor during each of these conditions in very distinct ways. Typically, during motor starting, locked rotor and acceleration conditions, the motor is rotor limited. That is to say that the rotor will approach its thermal limit before the stator. Under locked rotor conditions, voltage is induced in the rotor at line frequency, 50 or 60 Hz. This voltage causes a current to flow in the rotor, also at line frequency, and the heat generated (I2R) is a function of the effective rotor resistance. At 50 or 60 Hz, the reactance of the rotor cage causes the current to flow at the outer edges of the rotor bars. The effective resistance of the rotor is therefore at a maximum during a locked rotor condition as is rotor heating. When the motor is running at rated speed, the voltage induced in the rotor is at a low frequency (approximately 1 Hz) and therefore, the effective resistance of the rotor is reduced quite dramatically. During running overloads, the motor thermal limit is typically dictated by stator parameters. Some special motors might be all stator or all rotor limited. During acceleration, the dynamic nature of the motor slip dictates that rotor impedance is also dynamic, and a third overload thermal limit characteristic is necessary. The figure below illustrates typical thermal limit curves. The motor starting characteristic is shown for a high inertia load at 80% voltage. If the motor started quicker, the distinct characteristics of the thermal limit curves would not be required and the running overload curve would be joined with locked rotor safe stall times to produce a single overload curve. The motor manufacturer should provide a safe stall time or thermal limit curves for any motor they sell. To program the 469 for maximum protection, it is necessary to ask for these items when the motor is out for bid. These thermal limits are intended to be used as guidelines and their definition is not always precise. When operation of the motor exceeds the thermal limit, the motor insulation does not immediately melt. Rather, the rate of insulation degradation has reached a point that motor life will be significantly reduced if it is run any longer in that condition. The primary protective function of the 469 is the thermal model. It consists of five key elements: the overload curve and overload pickup level, the unbalance biasing of the motor current while the motor is running, the motor cooling time constants, and the biasing of the thermal model based on Hot/Cold motor information and measured stator temperature. Each of these elements are described in detail in the sections that follow. The 469 integrates stator and rotor heating into one model. Motor heating is reflected in the A1 STATUS ? MOTOR STATUS ?× MOTOR THERMAL CAPACITY USED actual value register. If the motor has been stopped for a long period of time, it will be at ambient temperature and the
