An electric power steering apparatus has a steering mechanism SM having universal joints 4, 6 in a torque transmitting system, a steering toque detecting unit 14, a steering angle detecting, unit 18, a torque fluctuation detecting unit 43 for detecting a torque fluctuation due to the crossing angle α in the universal joints 4, 6 on the basis of the steering angle θ detected by the steering angle detecting unit 18 and any one of the steering torque T detected by the steering torque detecting unit, a current command value It and self-aligning torque SAT; and a current command value correcting unit 44 for correcting the current command value on the basis of the torque fluctuation detected by the torque fluctuation detecting unit 43 and the steering angle θ detected by the steering angle detecting unit 18.

Electric Power Steering Apparatus

A water heater including a water inlet line having an inlet opening that introduces cold water to a tank, a water outlet line having an outlet opening that withdraws heated water from the tank, and a heating element. The water heater further includes a control circuit. The heating element can be an electrical resistance heating element, a gas heating element, or a combination thereof. In one construction, the gas heating element includes a first combustive section and a second combustive section separately controlled from the first combustive section.

Water heater and method of controlling the same

A method and apparatus is provided for monitoring and controlling the temperature at the heat producing portion of an electrical current carrying device without direct measurement at the heat producing site. An integrated circuit 22 is thermally attached to a plurality of heat dissipating paths; top side heat conduction path 24, bottom side heat conduction path 26, and board level heat conduction path 28. On one of the heat conduction paths exists a heat flow sensor. This sensor is comprised of an inner thermistor 32 and an outer thermistor 34. The measured heat flow is combined with a single point temperature measurement and the thermal conductivity between the heat source and the temperature measurement point to produce the temperature at the heat source. This temperature is monitored in order to keep the temperature of the electrical current carrying device below critical levels or within a specified range.

Method of junction temperature determination and control utilizing heat flow

A storage-type water heater and method of operating the storage-type water heater. The water heater includes a water tank for storing water, at least one heating element to heat the stored water, a jacket surrounding at least a portion of the tank, and a control system for controlling the water heater. In one construction of the water heater, the water heater includes two heating elements, and the control system includes three temperature sensors and two moisture sensors. The control system can also include circuitry for detecting errors and change operation of the water based on a detected error.

Water heater and method of operating the same

A method of determining whether water is surrounding a heating element of a water heater, the method comprising the acts of: applying a signal to the heating element; measuring a first resistance of the heating element; measuring a second resistance of the heating element after measuring the first resistance; determines whether the heating element is surrounded by water by comparing the first resistance with the second resistance; wherein the act of measuring a first resistance includes the acts of: obtaining a second signal proportional to the first signal; applying the second signal to a first amplifier resulting in a third signal; sensing a current of the first signal; obtaining a fourth signal proportional to the sensed current; applying the fourth signal to a second amplifier resulting in a fifth signal; and calculating the first resistance in response to the third and fifth signal.

Method and apparatus for detecting a dry fire condition in a water heater

An operating circuit for a semiconductor switch device of the type that passes electrical current from a source to an electrical load by forward biasing of the semiconductor's control terminal includes a resistance bridge network having in an arm thereof the control terminal to one main terminal circuit of the semiconductor switch, and a bias control for alternately applying forward bias and reverse bias to the control terminal through the bridge network, whereby a voltage is developed across the bridge output during the interval in which the control terminal is reverse biased that is representative of the junction temperature within the semiconductor. The temperature representative voltage is observed, monitored, and used for indication and control. In a further embodiment the bias control operated periodically and includes inhibit means responsive to the derived temperature representative voltage exceeding a certain level, representative of a temperature maximum, for retaining the control terminal of the semiconductor in the back biased condition, until the derived voltage reduces in level thereby protecting the semiconductor from thermal burn-out. In a welding control circuit presented herein the foregoing bias control is adapted in an intra-phase control circuit.

James Kirk Mathews

Papers

Electrical operating circuit having semiconductor device junction temperature monitoring