IS200AEADH1A工业卡件,机械设备卡件
管理继电器4-31 4设定点编程4.6 S5热模型4 a）功能过载曲线说明了定子和转子在失速、加速和运行期间的电机加热。当电机进入过载状态时，OVERLOAD PICKUP LEVEL（过载拾取水平）设定值指示运行过载曲线的开始位置。这对于使用系数电机很有用，因为它允许定义拾取水平。当电流值低于该拾取值时，曲线被有效地切断。根据三种运行条件，电机热极限由三个不同部分组成：锁定转子或失速、加速和运行过载。可以为热电机和冷电机提供这些曲线中的每一个。热电机是指在满负荷下运行一段时间，使得定子和转子温度稳定在其额定温度的电机。冷电机是指停止一段时间，使定子和转子温度稳定在环境温度的电机。对于大多数电机，电机热极限的不同特性形成了平滑的均匀曲线。有时只提供安全的失速时间。如果电机设计保守，并且能够在不影响热极限的情况下轻松完成所需的工作，这是可以接受的。在这种情况下，保护可以是保守的，并且过程完整性不会受到损害。如果电机在按要求运行时设计得非常接近其热极限，则热极限的独特特性变得重要。469过载曲线可以采用三种格式之一：标准、自定义曲线或电压相关。无论所选曲线样式如何，热存储器都保留在A1状态\电机状态\热容量已用寄存器中。使用以下公式每100 ms更新一次该寄存器：其中：time_to_trip=根据FLA从Ieq处的过载曲线获取的时间。过载保护曲线应始终设置为略低于制造商提供的热限值。这将确保电机在达到热极限之前跳闸。如果电机启动时间在安全失速时间内，建议使用469标准过载曲线。标准过载曲线是一系列15条曲线，具有基于典型电机热极限曲线的共同曲线形状
agement Relay 4-31 4 SETPOINT PROGRAMMING 4.6 S5 THERMAL MODEL 4 a) FUNCTION The overload curve accounts for motor heating during stall, acceleration, and running in both the stator and the rotor. The OVERLOAD PICKUP LEVEL setpoint dictates where the running overload curve begins as the motor enters an overload condition. This is useful for service factor motors as it allows the pickup level to be defined. The curve is effectively cut off at current values below this pickup. Motor thermal limits consist of three distinct parts based on the three conditions of operation: locked rotor or stall, acceleration, and running overload. Each of these curves may be provided for a hot and a cold motor. A hot motor is defined as one that has been running for a period of time at full load such that the stator and rotor temperatures have settled at their rated temperature. A cold motor is defined as a motor that has been stopped for a period of time such that the stator and rotor temperatures have settled at ambient temperature. For most motors, the distinct characteristics of the motor thermal limits are formed into a smooth homogeneous curve. Sometimes only a safe stall time is provided. This is acceptable if the motor has been designed conservatively and can easily perform its required duty without infringing on the thermal limit. In this case, the protection can be conservative and process integrity is not compromised. If a motor has been designed very close to its thermal limits when operated as required, then the distinct characteristics of the thermal limits become important. The 469 overload curve can take one of three formats: Standard, Custom Curve, or Voltage Dependent. Regardless of the selected curve style, thermal memory is retained in the A1 STATUS\MOTOR STATUS\THERMAL CAPACITY USED register. This register is updated every 100 ms using the following equation: where: time_to_trip = time taken from the overload curve at Ieq as a function of FLA. The overload protection curve should always be set slightly lower than the thermal limits provided by the manufacturer. this will ensure that the motor is tripped before the thermal limit is reached. If the motor starting times are well within the safe stall times, it is recommended that the 469 Standard Overload Curve be used. The standard overload curves are a series of 15 curves with a common curve shape based on typical motor thermal limit curves
