Diagnostics for high-voltage machines The partial discharge diagnostics (TE) are a well-tested procedure for assessing the status of high-voltage machines. It is performed as offline or online measurement, depending on what the large drives are used for. To measure the TM signals, the patented Siemens Insulator Integrated Coupling Units can be optionally built into high-voltage motors at the factory. There are significant advantages to this option: Easy and low-cost installation No modification of the terminal box necessary Robust mechanical design Highest and tested integrity of the insulation distances Direct interface to status diagnostics