WIRELESS POWER TRANSFER

A power transmitter (101) transfers power to a power receiver (105) and comprises a power input (209) receiving supply power. A power detector (211) detects a restoring of the supply power following an outage, and a presence detector (213) detects the presence of the power receiver when supply power is being restored. A first communicator (207) can communicate with a second communicator (509) of the power receiver (105) using a short range communication channel. A message circuit (215) transmits a power restore message to the second communicator (509) when supply power is being restored. A user action detector (217) detects a power receiver user action and a controller (205) arranged to initiate a power transfer to the power receiver after power restoration in response to the detection of the user action and to inhibit initiation of the power transfer after power restoration if the user action is not detected. The power receiver (105) can generate a user alert when receiving the power restore message.