Set all seven transformers for 230V main supply

MULTIPLE WINDINGS AND JUMPERS

IBM makes use of transformers with multiple primary windings allowing them to make connections based on the input voltage range. Generally they support just three choices - 115V, 208V and 230V. The ALDs list tables for each transformer indicating which terminals should be used for the input voltage and where to place jumpers. 

Since this machine had wiring for 208V but will be used on single phase 240V circuits, I had to rewire the transformers to configure the machine properly. 

TRANSFORMERS TO ADJUST IN THIS 1130 SYSTEM

A transformer (T1) inside the power sequencer box generates the 24VAC that runs through the power switches and emergency power off buttons. This is the first that must be configured for the intended line voltage. 

A transformer in the machine behind the sequencer box (T2) converts the input voltage to 115VAC for certain circuits that must operate at this level. These include the cooling fans, the typewriter motor, and similar devices in peripherals hooked to the system. 

Another transformer in the machine outside of the sequencer box is T3, which powers the convenience outlet on the side of the 1130 and other convenience outlets in attached peripherals. 

The usage meters that IBM used to bill customers for the use of the system run on their own supply, placed in a tamper resistant box. This transformer also required configuration for 240V. 

The lamps on the display pedestal above the console printer are powered by a separate lighting power supply. Its transformer also must be configured for the input voltage by moving input wires and jumpers. 

Finally, the main power supply has two transformers inside it, T1 and T2 (not to be confused with the T1 and T2 at the start of this section). These are individually configured for input voltage, each with their own jumpers and input terminals. 

For this particular machine, the seven transformers were all that are installed.