BY GEORGE LANTHIER

This is taken from another of our Wiring Books , in fact it comes from Volume One , Fundamentals .

STEP-UP TRANSFORMERS

The most common use of this type of transformer is around oilburning equipment and is the ignition transformer . This transformer is similar in construction to the step-down with its iron core and windings , but instead of lowering the power output it increases it . In Figure 5-11 we see an example of a typical ignition transformer for oilburners . This transformer ’ s primary coil would be normally operated at 120 Vac at a draw of about 2 amps . On its secondary coil it would normally produce 10,000 Vac at about . 023 amps or 23 milliamps . Ignition transformers are generally ‘ mid-point grounded ’. Midpoint grounding allows these transformers producing a high-intensity arc to operate without producing interference that can affect radios , televisions and computers .

Figure 5-11

In Figure 5-12 we see an example of a new type of oilburner ignitor . These ignitors produce a spark ranging from 8,000 volts to 14,000 volts electronically , depending on the manufacturer . This type of ignitor is similar to those used in automotive solid-state ignition systems . A transformer is constructed of two coils made of copper wire and an iron magnet insulated with tar . An ignitor is an electronic component constructed from transistors and diodes and normally insulated with epoxy .

Figure 5-12

TROUBLESHOOTING

Although there are many procedures for testing a conventional ignition transformer , the most basic procedure to test the conventional transformer is the oldest , and requires only a well-insulated screwdriver free of cracks and damage . I am much less concerned about someone working on 10,000 volts at 23 milliamps than someone going into an ungrounded 120-volt circuit with 15 amps of potential . Before you speak or teach know what you ’ re talking about , FACT ! The facts are that you must learn to work with and respect all voltages and more importantly amperages around HVAC equipment and if you know what you ’ re doing then this is no more dangerous than anything else . If you don ’ t know what you ’ re doing , learn ! In Figure 5-13 you see this procedure illustrated .

Figure 5-13

• Take a well-insulated screwdriver and touch the shaft to one of the two ignitor terminals . Keep all parts of your body at least one inch from any components including the screwdriver shaft .

• Turn on the power , and bring the tip of the screwdriver to the other terminal .

• Pull the tip away , and a strong spark of at least ¾ inch should be created , and maintained .

If the transformer will not pass this test , replace it .

NOTE : This test may also be done on solid-state ignitors and a spark of at least one inch should be obtained . Refer to the manufacturer ’ s literature for other testing procedures .

Figure 5-14

In Figure 5-14 you see a procedure for checking electrodes .

• Place a booted jumper across the ignitor tips .

• Again , take a well-insulated screwdriver and jumper the shaft to a known ground .

• Turn on the power , and bring the tip of the screwdriver to the surface of the ignitor .

• There should be no arcing across any surface of the ignitor .

• Check both ignitors , and if the ignitor insulators will not pass this test , replace them .

Here ’ s a few more ‘ tricks of the trade ’ for use around ignition transformers . The use of a transformer tester can be of help in determining many problems with transformers . In Figure 5-15 we show an

Figure 5-15

36 OCTOBER 2021 | FUEL OIL NEWS | www . fueloilnews . com