Motors with what power rating or higher require the installation of temperature-sensing platinum resistors?
Thread Content
For motors with what power rating or higher is it necessary to install temperature-sensing platinum resistors, and which standards specify this?
1. GB755-2008 Rotating electrical machines – Ratings and performance 8.6.1 Selection of method For the stator windings of AC electrical machines with a rated output of 5000 kW (or kVA) or more, the embedded thermocouple method shall be used. For AC motors with a rated output of 5000 kW (or kVA) or less but above 200 kW (or kVA), unless otherwise specified, the manufacturer shall use the resistance method or the embedded thermocouple method. For AC motors with a rated output of 200 kW (or kVA) or less, unless otherwise specified, the manufacturer shall use the direct measurement method based on resistance or the superposition method (see 8.6.2.1) (see also below). For motors with a rated output of 600 W (or kVA) or less, when the windings are not evenly distributed or when the wiring is overly complex due to necessary connections, a thermometer can be used to measure the motor’s temperature rise. For AC stator windings with only one coil per slot, the resistance method should be used instead of the embedded thermocouple method. However, some designers in design firms require the use of thermal resistors when the rated output power of the motor is 120 kW or higher, or even at lower levels as well (it mainly depends on the individual). GB/T 13957 – Basic series technical requirements for large three-phase asynchronous motors. This standard applies to Y-series three-phase asynchronous motors with cage rotors intended for general use (hereinafter referred to as Y-series motors), as well as YR-series three-phase asynchronous motors with wound rotors also intended for general use (hereinafter referred to as YR-series motors). The rated frequency of these motors is 50 Hz, and their rated voltage is either 6000 V or 10000 V. Clause 4.18 stipulates that the stator windings shall be equipped with 6 embedded resistance temperature sensors of the PT100 type; each bearing shell shall be equipped with 1 resistance temperature sensor of the PT100 type.