HONEYWELL 51454408-175 CC-PDOD51系統模塊卡件
電流不平衡分別為6、12、18、24和30%。基于此假設，GE Multiline曲線說明了為UNBALANCE BIAS k FACTOR（不平衡偏置k系數）設定值輸入的不同k值的電機降額。注意，當k=8時創建的曲線幾乎與NEMA降額曲線相同。圖4–12：由于電壓不平衡導致的中等電機減額因數如果輸入k值為0，則不平衡偏置將失效，過載曲線將根據測量的每單位電機電流超時。k可以保守計算為：（EQ 4.4）e）電機冷卻當電機電流小于過載拾取設置點時，所用熱容量值呈指數下降。這種減少模擬了電機冷卻。應輸入停止和運行情況下的電機冷卻時間常數。由于冷卻是指數型的，時間常數是從100%熱容量到0%總時間的五分之一。停止的電機通常比運行的電機冷卻得慢得多。電機冷卻計算為：（EQ 4.5）（EQ 4.6）其中：TCused=熱f）熱/冷曲線比率電機制造商可提供熱/冷電機的熱極限信息。如果編程了熱/冷曲線比率設定值，469熱模型將適應這些條件。該設定值規定了繼電器在電流水平低于過載拾取水平時所使用的熱容量水平。當電機以低于過載拾取水平的水平運行時，所用熱容量寄存器將上升或下降至基于平均相電流和熱/冷曲線比率設定值的值。所用熱容量將以每分鐘5%的固定速率上升，或根據運行冷卻時間常數下降。（EQ 4.7）式中：TCused_end=如果Iper_unit保持穩定狀態，則使用的熱容量Ieq=等效電機加熱電流熱/冷=熱/冷曲線比率設定值熱/冷的曲線比率可根據熱極限曲線（如果提供）或熱/冷安全失速時間確定。只需將熱安全失速時間除以冷安全失速時間。如果不提供熱時間和冷時間，不能有任何差異，熱/冷曲線比率應輸入為“1.00”。808705A1.CDR 0 25 50 75 100 0 30 60 90 150 180時間（以分鐘為單位）使用的熱容量冷卻時間常數=15分鐘TCused_start=85%熱/冷比率=80%Ieq/過載拾取=100%0 25 50 100 0 30 90 120 150 180時間，以分鐘為分鐘使用的熱能力冷卻時間常數=15分鐘TCused_start=85%熱/冷比=80%Ieq/過載拾取=80%0 25 50 75 100 0 30 60 90 120 150 180分鐘熱容量使用冷卻時間常數=30分鐘TCused_start=85%熱/冷比率=80%電機在運行額定負載后停止TCused_end=0%0 25 50 100 30 60 90 150 180分鐘冷容量使用冷卻溫度常數=30 min TCused_start=100%熱/冷比例=80%電機停止過載跳閘后TCused_end=0%電機跳閘100%負載電機停止80%負載TCused_end Ieq 1熱-冷? ? ? ? = ××100%GE Multilin 469電機管理繼電器4-41 4設定值4.6 S5熱模型4 g）RTD偏置469熱復制品作為一個完整的獨立模型運行。然而，熱過載曲線僅基于測量電流，假設環境溫度為40°C，電機冷卻正常。如果環境溫度異常高，或電機冷卻受阻，電機溫度將升高。如果電機定子具有嵌入式RTD，則應使用469 RTD偏置特性來校正熱模型。RTD偏置特性為兩部分曲線，由3個點構成。如果最大定子RTD溫度低于RTD偏置最小設定值（通常為40°C），則不會發生偏置。
current unbalances of 6, 12, 18, 24, and 30% respectively. Based on this assumption, the GE Multilin curve illustrates the motor derating for different values of k entered for the UNBALANCE BIAS K FACTOR setpoint. Note that the curve created when k = 8 is almost identical to the NEMA derating curve. Figure 4–12: MEDIUM MOTOR DERATING FACTOR DUE TO UNBALANCED VOLTAGE If a k value of 0 is entered, the unbalance biasing is defeated and the overload curve will time out against the measured per unit motor current. k may be calculated conservatively as: (EQ 4.4) e) MOTOR COOLING The thermal capacity used value decreases exponentially when the motor current is less than the OVERLOAD PICKUP setpoint. This reduction simulates motor cooling. The motor cooling time constants should be entered for both stopped and running cases. Since cooling is exponential, the time constants are one-fifth of the total time from 100% thermal capacity used to 0%. A stopped motor normally cools significantly slower than a running motor. Motor cooling is calculated as: (EQ 4.5) (EQ 4.6) where: TCused = thermal f) HOT/COLD CURVE RATIO The motor manufacturer may provide thermal limit information for a hot/cold motor. The 469 thermal model adapts for these conditions if the HOT/COLD CURVE RATIO setpoint is programmed. This setpoint value dictates the level of thermal capacity used the relay will settle at for current levels below the OVERLOAD PICKUP LEVEL. When the motor is running at a level that is below the OVERLOAD PICKUP LEVEL, the THERMAL CAPACITY USED register will rise or fall to a value based on the average phase current and the HOT/COLD CURVE RATIO setpoint. The THERMAL CAPACITY USED will either rise at a fixed rate of 5% per minute or fall as dictated by the running cool time constant. (EQ 4.7) where: TCused_end = THERMAL CAPACITY USED if Iper_unit remains steady state Ieq = equivalent motor heating current hot / cold = HOT/COLD CURVE RATIO setpoint The HOT/COLD CURVE RATIO may be determined from the thermal limit curves if provided or the hot and cold safe stall times. Simply divide the hot safe stall time by the cold safe stall time. If hot and cold times are not provided, there can be no differentiation and the HOT/COLD CURVE RATIO should be entered as "1.00". 808705A1.CDR 0 25 50 75 100 0 30 60 90 120 150 180 Time in Minutes Thermal Capacity Used Cool Time Constant= 15 min TCused_start= 85% Hot/Cold Ratio= 80% Ieq/Overload Pickup= 100% 0 25 50 75 100 0 30 60 90 120 150 180 Time in Minutes Thermal Capacity Used Cool Time Constant= 15 min TCused_start= 85% Hot/Cold Ratio= 80% Ieq/Overload Pickup= 80% 0 25 50 75 100 0 30 60 90 120 150 180 Time in Minutes Thermal Capacity Used Cool Time Constant= 30 min TCused_start= 85% Hot/Cold Ratio= 80% Motor Stopped after running Rated Load TCused_end= 0% 0 25 50 75 100 0 30 60 90 120 150 180 Time in Minutes Thermal Capacity Used Cool Time Constant= 30 min TCused_start= 100% Hot/Cold Ratio= 80% Motor Stopped after Overload Trip TCused_end= 0% MOTOR TRIPPED 100% LOAD MOTOR STOPPED 80% LOAD TCused_end Ieq 1 hot cold – ---------- ? ? ? ? = × × 100% GE Multilin 469 Motor Management Relay 4-41 4 SETPOINTS 4.6 S5 THERMAL MODEL 4 g) RTD BIAS The 469 thermal replica operates as a complete and independent model. The thermal overload curves however, are based solely on measured current, assuming a normal 40°C ambient and normal motor cooling. If the ambient temperature is unusually high, or if motor cooling is blocked, the motor temperature will increase. If the motor stator has embedded RTDs, the 469 RTD bias feature should be used to correct the thermal model. The RTD bias feature is a two-part curve, constructed using 3 points. If the maximum stator RTD temperature is below the RTD BIAS MINIMUM setpoint (typically 40°C), no biasing occurs.
