Available online
Description
The TV programme introduces the topic firstly by explaining what a transformer is and how it works, and secondly illustrating some of the problems associated with the design of large transformers.
The TV programme introduces the topic firstly by explaining what a transformer is and how it works, and secondly illustrating some of the problems associated with the design of large transformers.
| Module code and title: | TS251, An introduction to materials |
|---|---|
| Item code: | TS251; 10 |
| First transmission date: | 09-06-1973 |
| Published: | 1973 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:03 |
| + Show more... | |
| Producer: | Jim Stevenson |
| Contributors: | Ian Lowe; Charles Newey |
| Publisher: | BBC Open University |
| Keyword(s): | Design problems; Function; Heat loss; Hysteresis effect; Magnetism; Magnetostriction noise; National grid; Transformer |
| Footage description: | Charles Newey introduces the programme. He explains that it will examine the efficiency of large electric transformers which step up voltage for transmission at electric power stations. Newey shows several laminations from a transformer core. Newey holds up a piece of polished etched mild steel. No detail of crystal structure can be seen. Newey then holds up a lamination which has been etched. Details of crystal structure are clearly visible. Shots of a model of a community showing houses at various distances from a power station. Commentary explains why transformers are needed to transmit electricity over a distance (both step up and step down transformers). Newey introduces Ian Lowe who will examine some of the theory of transformers. Ian Lowe assembles a small transformer in the studio and as he does so, he explains the basic physics of transformers. He then explains how the efficiency of his transformer can be calculated and shows where losses occur. Power into the primary circuit and out of the secondary circuit is monitored. Lowe explains why transformer cores are made up of several laminations rather than a solid iron core. He places a solid iron core into his transformer. Eddy currents dissipate power. Lowe continues his explanation of the greater efficiency of laminations over solid iron cores. Lowe uses a.small transformer to examine the remnant magnetism phenomenum in transformer cores after power is switched off. Several cores are placed into the transformer and readings shown on the oscilloscope screen AC current of 50 cycles is used. The curves for ordinary mild steel and for transformer steel cores are compared. Both are compared with a curve for tool steel. Charles Newey demonstrates energy loss in transformers with a small transformer connected to a light bulb. The transformer is switched on and a buzzing noise is heard. Newey points out that noise and heat are major problems in large transformers. Shots of large transformers at an electricity generating station. Shots of a transformer core being manufactured and assembled. Shots of transformer coils being assembled. Shots of coil being lowered on the core. Shots of coil/core being lowered into an oil filled housing (oil acts as coolant). Commentary also explains how noise from magneto striction is made tolerable. Shots of a large transformer being transported by road to its site. Newey with laminations of a small transformer core. He sums up the programme. Credits over a still shot of a large transformer. |
| Master spool number: | 6HT/70884 |
| Production number: | 00525_5036 |
| Videofinder number: | 1562 |
| Available to public: | no |
