On the top row of terminals I have w1, v1, and u1 which I get are connected to v2, u2, and w2 on the second row of terminals. Now, on the bottom row of terminals are two wires labeled 3 and 4. Any idea what they are for and how I should connect them?
4\$\begingroup\$ Manufacturer, model number, datasheet? The two extra terminals may be for a temperature sensor in the motor to prevent overheating. What is the resistance measured between those terminals? \$\endgroup\$– UweNov 5, 2022 at 16:55
\$\begingroup\$ Hi Uwe, thank you do much for your reply, so would I just connect those two to U2 and W2 ? \$\endgroup\$– Douglas van DykNov 6, 2022 at 15:59
\$\begingroup\$ At first you should measure the resistance between those two terminals. \$\endgroup\$– UweNov 6, 2022 at 17:07
\$\begingroup\$ Resistance is 1 ohm \$\endgroup\$– Douglas van DykNov 7, 2022 at 16:58
\$\begingroup\$ If the resistance is 1 ohm I would guess a thermo switch that will open when temperature of the motor windings is getting to hot. You should use a motor protect unit together with this motor for overcurrent and overtemperature protection. The thermoswitch should be connected to the unit. \$\endgroup\$– UweNov 8, 2022 at 8:00
It could be a 3 phase, delta-connected motor with thermistor protection against overheating (three series-connected PTC thermistors embedded in the windings and terminated as shown).
The thermistors would enable a thermistor relay at normal temperature and disable the same at a higher temperature.
The thermistor relay, in turn, would enable / disable the motor power contactor.