Knudsen Engineering Ltd (KEL), located in Perth, Ontario, is an engineering firm specializing in the development and construction of a wide range of echosounding equipment. Echosounders are used to measure the depth of marine floors by sending out ultrasonic pulses through the water and measuring the time taken for the pulse to return to the echosounder, as illustrated in Figure 1. The transducers that send and receive the ultrasound pulses can be configured in different ways, each variation having possibly different impedance loads. If an echosounder with a different impedance load than the transducer is used, the output power of the pulses are either increased or decreased depending on the setup. If the power is too high, it can cause damage to the echosounder and the transducers, and if it is too low, the pulse won’t be able to reach the marine floor. One of KEL’s high-power echosounder products, the CHIRP 3260, is capable of reaching depths of 10,000 meters or more. To generate sufficient power, this product required to incorporate an external matching transformer.
Nathan Landsman, a Mechanical Engineering student from the University of Waterloo, was asked to design and build both the electrical and enclosure components of a transformer that will be used to handle the impedance load of the transducers.
The teaching objectives for this case study are to examine the limitations of supplied power in a circuit, to use transformer characteristics for impedance matching, and to design electrical devices with concern for physical limitations of size and weight. The case can be used effectively to illustrate electrical and mechanical design for a transformer. This case will also give students the opportunity to be introduced to the power unit selection issues associated with metering and related electrical system design. The case study is intended as an example of transformer design in Power Systems and Components (ECE 361).