SIEMENS MT0750M – 750VA - INDUSTRIAL CONTROL TRANSFORMER, 750VA 208/277 – 120V

Description

SIEMENS MT0750M – 750VA - INDUSTRIAL CONTROL TRANSFORMER, 750VA 208/277 – 120V
Industrial Control Power Transformers
Class MT
Features
Epoxy-encapsulated (50–750VA); epoxy resin impregnated (1.0–5.0 KVA). Completely seals the transformer coils against moisture, dust, dirt and industrial contaminants for maximum protection in hostile and industrial environments.
Fuse clips (most models). Factory mounted for integral fusing on the secondary side to save panel space, save wiring time and save the cost of buying an add-on fuse block or kit.
Integrally molded barriers. Between terminals and transformer, protect against electrical creepage. Up to 30% greater terminal contact area permits low-loss connections. Extra-deep barriers reduce the chance of shorts from frayed leads or careless wiring.
Terminals. Molded into the transformer, are difficult to break during wiring. A full quarter-inch of thread on the 10-32 terminal screws prevents stripping and pullout.
Operation
Industrial control circuits and motor control loads typically require more current when they are initially energized than under normal operating conditions. This period of high current demand, referred to as inrush, may be as great as ten times the current required under steady state (normal) operating conditions, and can last up to 40 milliseconds. A transformer in a circuit subject to inrush will typically attempt to provide the load with the required current during the inrush period. However, it will be at the expense of the secondary voltage stability by allowing the voltage to the load to decrease as the current increases. This period of secondary voltage instability, resulting from increased current, can be of such magnitude that the transformer is unable to supply sufficient voltage to energize the load. The transformer must therefore be designed and constructed to accommodate the high inrush current, while maintaining secondary voltage stability. According to NEMA standards, the secondary voltage would typically be at 85% of the rated voltage. Industrial Control Power Transformers are specifically designed and built to provide adequate voltage to the load while accommodating the high current levels present at inrush. These transformers deliver excellent secondary voltage regulation and meet or exceed the standards established by NEMA, ANSI, UL and CSA. Their rugged construction and excellent electrical characteristics ensure reliable operation of electromagnetic devices and trouble-free performance.
Specifications
Laminations are built with silicon steel to minimize core losses and to increase optimum performance and efficiency.
Copper magnet wire of the highest quality assures efficient operation.
Factory mounted type
“
K
”
fuse clips are standard on all secondary transformers where possible.
UL listed and CSA certified.
50/60 Hz rated.
Insulation materials are of the highest rating available for the temperature class.
Mounting brackets are heavy gauge steel to add strength to core construction and provide stable mounting. Slotted mounting feet permit easy installation.
Attractive black finish; easy-to-read nameplate with complete rating data and wiring diagram.
Class 105
°
C (221
°
F) insulation system. 55°C (131°F) temperature rise. (50–750VA
typical)
Class 180
°
C (356
°
F) insulation system. 120°C (248°F) temperature rise. (1000–5000VA typical)
Transformer Selection Process
Selecting a transformer for industrial control circuit applications requires knowledge of the following terms:
Inrush VA
is the product of load voltage (V) multiplied by the current (A) that is required during circuit start-up. It is calculated by adding the inrush VA requirements of all devices (contactors, timers, relays, pilot lights, solenoids, etc.), which will be energized together. Inrush VA requirements are best obtained from the component
manufacturer.
Sealed VA
is the product of load voltage (V) multiplied by the current (A) that is required to operate the circuit after initial start-up or under normal operating conditions. It is calculated by adding the sealed VA requirements of all electrical components of the circuit that will be energized at any given time. Sealed VA requirements are best obtained from the component manufacturer. Sealed VA is also referred to as steady
state VA.
Primary Voltage
is the voltage available from the electrical distribution system and its operational frequency, which is connected to the transformer supply voltage terminals.
Secondary Voltage
is the voltage required for load operation which is connected to the transformer load voltage terminals. (120v)