Type ``2`` Requires that, under short-circuit conditions, the contactor or starter shall cause no danger to persons or installation and shall be suitable for further use. The risk of contact welding is recognized, in which case the manufacturer shall indicate the measures to be taken as regards the maintenance of the equipment. (No damage is allowed to either the contactor or overload relay. Light contact welding is permitted, but contacts must be easily seperable. No damage protection typically can only be provided by a currentlimiting device.) Type ``2`` Coordination (No-Damage Protection) for IEC and NEMA devices assures that the motor starter will be operable after a fault occurs and the fault corrected. Type ``2`` Coordination (No-Damage Protection) cannot prevent the initial fault from occurring. However, it assures all other components in the motor starter remain functional.
To obtain Type ``2`` Coordination (No-Damage Protection) with either IEC or NEMA devices, motor starter manufacturers evaluate and test each combination of contactor, overload relay, and short-circuit protective device. The tests are as follows:
A discrete low level fault test is performed at rated voltage.
A high level short circuit withstand test, such as 100,000 amps, at rated voltage, is performed to check for the integrity of the contactor and overload relay.
An overload relay and calibration test verifies operating characteristics and reliability. This test is performed before and after the low and high-level fault tests to determine if the overload relays sustained any damage during the test.
Dielectric tests are performed to prove insulation adequacy after the low and high-level fault current tests have been completed.