Tank : The reservoir or sump.

Tachometer: A device which generates an AC or DC signal proportional to the speed at which it is rotated and the polarity of which is dependent on the direction of rotation of the rotor.

TENV (Total Enclosed Non-Ventilated): Acronym describing a type of motor enclosure, which has no outside air going into it. It is cooled only by convection to the frame, which is usually finned.

Throttle: To permit passing of a restricted flow. May control flow rate or create a deliberate pressure drop.

Thermal Resistance (Rth) (0^c/watt): An indication of how effectively a unit rids itself of heat, a measure of temperature rise per watts lost. In Powertec Industrial Motors literature, it is the specified value from the motor windings to the ambient , under locked rotor condition.

Thermostat: A temperature sensitive pilot duty device mounted on the interior of the motor to protect it from over heating.

Thermal protection: A thermal sensing device mounted to the motor to protect it from overheating. This is accomplished by disconnecting the motor phases from the drive in an temperature condition.

Transducer: A device that converts one type of energy to another. An example would be the transducer sensing pressure and generating an electrical signal in proportion to the pressure.

Torque: Force tending to produce rotation.

Torque Constant: K_T= The torque generated in a Dc motor per unit Ampere applied to its windings.
K_T = T_oz-in / A_amp
Simplified for a brushless motor at 90⁰ commutation angle.

Torque Ripple: The cyclical variation of generated torque at a frequency given by the product of motor angular velocity and number of commutator segments or magnetic poles.

Torque-to-Inertia Ratio: Defined as a motor's holding torque divided by the inertia of its rotor. The higher the ratio, the higher a motor's maximum acceleration capability will be.

Triggers: Inputs on a controller that initiates or trigger the next step in a programm.

TTL: Transistor-Transistor Logic, Describes a common digital logic device family that is used in most modern digital electronics. TTL signals have two distinct states that are described with a voltage-a logical "zero" or "low" is represented by a voltage of less that 0.8 volts and a logical "one" or "high" is represented by a voltage from 2.5 to 5 volts.

Turbulent Flow (Turbulenece): A condition where the fluid particules move in random paths rather than in continues paralle path.

Turbine. A rotary device that is actuated by the impact of a moving fluid against blades or vanes.

Twoway Valve: A directional control valve with two flow paths.