Control Panel (Part 2)
STEP 3: Install internal components
We have 10 components that need to be installed on the back plate:
- Two (2) 8 position terminal strips
- Three (3) 30A/240V DPDT or DPST relays with 120V AC coil
- Two (2) doorbell transformers (120VAC in, 8-24VAC out, any wattage)
- Two (2) adjustable DC power supplies (4-30V AC/DC input, 1.5-27V DC output)
- One (1) 50A shunt (included with the amp meter)
The best way to install components to a back plate is to create threaded holes so that nuts are not required on the back side. This makes future maintenance easier as the entire back plate does not have to be removed to gain access to a nut if a component needs replacing. To create threaded holes you need to use a tap and die set as shown in the installation of our heat sink in part 1. The components are installed using 3/16 x 3/4" stove bolts. The adjustable DC power supplies have parts close to the mounting holes so smaller 1/8 x 1/2" stove bolts were used instead. Drill pilot holes first using a high speed metal drill bit. Refer to your tap and die set for the correct size pilot hole for the bolt size you'll be using. Thread the holes using the correct size tap. Go slowly, turning the tap by hand and let the tap do the work. Clean off any metal shavings.
If you do not own a tap and die set, (Why not? They're inexpensive!), then you may simply drill the holes with a 3/16" high speed steel drill bit and use a metal file to smooth down any rough edges. Make sure to keep any metal filings out of the enclosure. Mount all of the items using 3/16 x 3/4" stove bolts and nuts. The adjustable DC power supplies have parts close to the mounting holes so smaller 1/8 x 1/2" stove bolts were used instead.
Unlike the other components, the DC power supplies cannot be bolted directly against the metal back plate as the circuit board will scratch through the orange paint and cause short circuits. Use small flat rubber washers or an extra nut or two on the bolt between the circuit board and the back plane to keep them separated. Better yet, use nylon standoffs and screws (included in our control panel kits or available separately with our power supplies).
Reinstall the back plate in the enclosure.
10 components are installed on the back plate: