A step down transformer is a transformer with a secondary voltage that is less than its main voltage. Its primary purpose is to decrease the voltage from the primary winding to the secondary winding. This type of transformer converts low-current, high-voltage power to high-current, low-voltage power. The wire used in the secondary winding is important because of the current increase, and is made with a larger gauge. The primary winding can be made of smaller-gauge wire, since it won’t conduct much current. Read on and learn how to wire a step down transformer.
First, you need to determine what the schematic will look like before you start working with any materials. At the transformer’s lower side is the terminal connection box cover; remove this because only those with high amperages require such enclosure. Next, make sure that you are familiar with the termination identification of step down transformers. H1, H2, H3 and H4 refer to the transformer’s power feed end. This applies to any transformer size.
Cut the wires to length and terminate the feed power wires. With large wire lugs, make sure that you consider the length of the lug as well as the amount of wire that can be installed into the female crimp area. After this, strip the outer insulation of the wires using wire strippers. Place an eye ring over the bare copper wire and crimp the connection device permanently to the wire, using the right-size crimper.
Terminate the high-voltage, high-side of the step down transformer. If you see that the high side terminals are bolts, ensure that you follow any torque requirements listed on the owner’s manual. Do the same with the low-voltage, low-side of the transformer. Remember that these terminals will be identified as X1, X2, X3 and X4. Once again, follow the individual directions stated in the manual for that particular type of transformer you are using.
Also terminate the small control transformer for X1 and X2. X1 will make its way to the control circuit after it passes through a small fuse within the circuit. X2 should only be terminated to the neutral side of the control unit and grounded for safety. In other words, the X2 side of the small control transformer has to be attached to the electrical unit’s grounding system.
Change all covers on the transformer, along with any enclosures that will provide protection from electrical damage. Switch on the feeder power circuit to put the high voltage to the transformer, and turn on the low side safety circuit control. Test for the appropriate voltage you are trying to achieve using a volt meter. Make sure that it matches the voltage indicated on the specifications tag provided by the transformer manufacturer.
Step down transformers are usually medium voltage transformers that convert 220 volt electricity to the 110 volts standard in North American. For more information and tips, contact an expert on step down or 3 phase transformer equipment to help you choose the right transformer and set it up on how you intend to use it.