How to Build a Trapeze for a 75 KVA Transformer
Using a trapeze for a transformer allows the transformer to exist in a limited-space environment. You can build your own trapeze by completing the following steps and the transformer will be ready for connection. As with any job that involves electricity, first eliminate all relevant electrical hazards by de-energizing them beforehand. Further, ensure safety by always wearing the appropriate safety gear when installing any electrical equipment. Safety gear includes safety glasses, a hard hat, leather gloves and safety shoes.
Measure the transformer’s width, and then add 6 inches.
Use the reciprocating saw to cut two pieces of strut channel, such as Unistrut, and then file the rough edges with the bastard file.
Press one strut channel piece against the ceiling where the transformer will hang and then mark the two end holes and the outside edge of the strut channel.
Use the transformer’s width to measure from the edge mark of the first strut channel to the adjacent side where the second strut channel will be hung in the same manner as Step 3. To ensure proper alignment of the transformer, use an I-beam or adjacent wall as a guide.
Follow the instructions on the box of anchors for the correct hole depth and then use the hammer drill to drill these holes at each of the four marked areas.
Insert an anchor into the first hole and set it in place using the set tool and hammer. Repeat this step with the remaining three holes.
Measure the height of the transformer and add a minimum of 6 inches for airflow over the top of the transformer.
Use the previous measurement to evenly mark four sections of the half-inch all thread. Prior to cutting the all thread, place a nut at each mark and then cut the all thread using the reciprocating saw. Use each nut for cleaning the resulting burrs at each end.
Place a nut, a lock washer and a flat washer on one end of each section of the all thread and then move these along the all thread until they sit 2 inches from the end of each section.
Insert one piece of all thread into an anchor and screw it in firmly, using the channel locks to tighten it. Repeat this step for the remaining three pieces.
Use the appropriate wrench to secure the nut against the anchor. Repeat this step for the remaining three pieces.
Use the equipment lift to raise the transformer off the ground just far enough to slide the strut channels under each side of the transformer.
Place one bolt, one lock washer and one flat washer into one of the mounting holes on the transformer mounting bracket, followed by placing the strut channel on the bolt and then adding a flat washer and a nut on the bolt to tighten it. Repeat this step for each remaining mounting bracket. If done correctly, the strut channel should face up with the flat side down and there should be about 3 inches of strut channel sticking out from each end of the transformer.
Place a nut on each piece of all thread hanging from the ceiling and move each nut up about 6 inches from the end of the all thread.
Position the transformer underneath the all thread and start raising it with the equipment lift.
Note when the transformer is close to the desired location and then place a lock nut and a flat washer on one all thread and feed it through the end hole of each channel strut. Repeat this step for the remaining three pieces of all thread.
Confirm that the transformer is in place and then move one flat washer and one nut about 1 inch from the end of each all thread section.
Slowly lower the transformer onto the flat washers.
Use the level and combination wrench to adjust the nuts on the bottom of each all thread section to level the transformer.
Lower the nuts that were previously placed at 6 inches on each all thread section and tighten them against the strut channels. Ensure that the transformer remains level during this step.
Things You Will Need
- Tape measure
- Reciprocating saw with bi-metal blade
- 20 feet of 1 5/8-inch strut channel, such as Unistrut
- Bastard file
- Hammer drill with masonary bit for 1/2-inch drop in anchors
- Four, ½-inch drop in anchors
- 1 set tool for drop in anchors
- 40 feet of ½-inch all thread
- ½-inch nuts (16)
- ½-inch lock washers (12)
- ½-inch flat washers (16)
- Four, ½-inch by 1 ¼-inch bolts
- Channel locks
- Combination wrenches to fit ½-inch nuts and bolts
- Equipment lift rated for weight of transformer
- This task will be easier with the additional help of one or two others.
- Electrical tape can be wrapped around the drill bit to use as a guide for appropriate drill depth.
- For Step 17, prevention of unnecessary bending of the all thread may be accomplished by raising the transformer slightly past the end of the all thread.
- Confirm that the equipment hoist is rated for more than the transformer weight.