An EM flipper coil is two windings

A flipper coil has a low-resistance power winding (around 3 ohms) for the flip and a high-resistance hold winding (around 125 ohms). When the EOS switch opens at the top of the stroke, the hold winding is put in series with the power winding so the flipper can be held up without burning.

Systems

• Electro-mechanical

Related tips

• Gottlieb flipper coil windings (power/hold)
• Replacing a flipper coil
• Flipper coil numbers carry two windings
• How an EM flipper coil and its EOS switch work
• Rebuild EM flippers before fitting stronger coils
• Bally and 1948-62 Williams (50 V) EM flipper coils
• Stronger flipper coils for Gottlieb EMs
• Gottlieb large flipper coils by wrapper colour

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part Two, Clay Harrell (pinrepair.com)