Monthly Archives: junho 2017

The Classification of Insulation

The American National Association Manufacturers Association (NEMA) has established insulation classes to meet the temperature requirements of electric motors found in different operating environments. It also standardized an ambient temperature of 40 ° C or 104 ° F within an altitude range defined for all classes of electric motors.

Vibration Rating: it is the maximum vibration that the motor can withstand and still meet the operational specifications.

Dust protection: protects against dust infiltration with features such as full-face sealing and labyrinth seals. The IP rating (input protection) for dustproof motors is IP6x.

baldor ECP3584T

Explosion Proof: They have fully enclosed housings that are built to withstand the internal explosion of a particular gas, vapor or dust. In the event of such an explosion, the casing would prevent ignition or explosion of the gas or vapor surrounding the engine compartment. Several explosion-proof ratings are governed by Underwriter’s Laboratories (UL).

Fully closed: they have a lock that prevents the free exchange of air between the indoor and outdoor environment. Common ratings are fan cooled and non-ventilated

Description of the Protection Circuit

The protection circuit comprises two protections: undervoltage and overcurrent. Overcurrent protection is intended to protect the circuit (especially the IGBTs – but also the tracks, connectors, power source) which are theoretically dangerous countercurrents and which generally indicate inadequate system operation (short circuit, Attempt to break the engine at high speeds, etc.).

The operation is based on the measurement of the voltage in resistors installed in series in the circuit (called “shunt”). The measured signal is amplified by op-amps and later equated with a reference set by the user. When the measured current exceeds the reference, the comparator changes state and the protection is preserved activated by the action of a flip-flop, until the user restarts the protection.

TDLT0750XM Transformer Disconnects

Because overcurrent protection is performed via hardware and fast components, it acts very quickly and efficiently. The adjustment of the actuation current is carried out by the user through a trimpot.

Once the limit is exceeded, in either arm of the inverter, the protection will act in a few microseconds. This protection works in addition to thermal protection.