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The advantages of using a buck-boost transformer over an equivalent
Standard Isolation Transformer are as follows:
Advantages
- Used in a variety of applications
- Inexpensive
- Smaller and lighter
- More efficient
- 5-10 times increase in KVA
Disadvantages
- No circuit isolation
- Cannot create a neutral
- KVA and voltages do not match what's on the nameplate KVA and voltages.
Buck-Boost Application
Buck-boost transformers offer an economical solution to the adjustment of line voltages that are slightly above or below
normal. When a Buck-Boost transformer is connected as an autotransformer, only a portion of the load kVA is actually
transformed. The majority of the load kVA is passed directly through to the source. For this reason a Buck-Boost transformer
may be used to supply a much larger load kVA than is indicated on the nameplate. Buck-Boost transformers can be used to adjust
stable voltages only. Fluctuating line voltages should be regulated with a
Line Voltage Conditioner.
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50 to 1000 VA |
1500 to 5000 VA |
| UL Listed |
File: E50394 |
File: E50394 |
| CSA Certified |
File: LR3902 |
File: LR3902 |
| Frequency |
50/60 Hz |
50/60 Hz |
| Insulation System |
130°C (80°C rise) |
180°C (115°C rise) |
| Standard Design |
Single Phase, welded core construction made with high quality, high permeability silicon steel laminations. Computer designed
coils, accurately wound from high quality copper magnetic wire. |
Single Phase, welded core construction made with high quality, high permeability silicon steel laminations. Computer designed
coils, accurately wound from high quality copper magnetic wire. |
| Encapsulation |
All units from 50VA to 5kVA are encapsulated with electrical grade silica sand and resin compounds. |
All units from 50VA to 5kVA are encapsulated with electrical grade silica sand and resin compounds. |
| Enclosure Type |
Heavy Duty Encapsulated NEMA Type 3R (Optional NEMA 4, 4X & 12 Available) |
Heavy Duty Encapsulated NEMA Type 3R (optional NEMA 4, 4X and 12 available) |
| Enclosure Finish |
ANSI 61 Grey, UL50 |
ANSI 61 Grey, UL50 |
| Termination |
Front accessible separate high and low voltage lead wires or copper tabs. |
Front accessible separate high and low voltage lead wires or copper tabs. |
| Conduit Knock-Outs |
Side and Rear standard on all units. |
Side and Rear standard on all units. |
| Mounting |
Standard Wall Mounting. |
Standard Wall Mounting. |
Voltage Is the Key
Buck-Boost transformers represent an economical way to both raise supply voltage caused by line drop or equipment demand on the
distribution system, or lower voltage caused by increased system voltages due to supply line adjustments. Some loads including
lighting and resistive loads require a stable supply to maintain performance. The detrimental effects of incorrect supply line
voltage can cause equipment failure. Buck-Boost transformers can correct line voltage within 5 to 25% of nominal.
Steps for Selecting Buck-Boost Transformers
The following information is required before selecting a buck-boost transformer:
- Line Voltage - The voltage that you want to buck (decrease) or boost (increase). This can be determined by measuring the
supply line voltage with a voltmeter.
- Load Voltage - The voltage at which your equipment is designed to operate. This is listed on the nameplate of the load
equipment.
- Load kVA or Load Amps - You do not need to know both - one or the other is sufficient. This information usually can be
found on the nameplate of the equipment that you want to operate. It is the sum of all the equipment that represents the load.
- Frequency - The supply line frequency must be the same as the equipment to be operated - either 50 or 60 Hertz.
- Phase - The supply line should be the same as the load - either single or three phase.
Four Steps to Select the Correct Buck-Boost Transformer
- Select a "high voltage" and "low voltage" combination that is the closest to matching the high voltage and low voltage
correction that is required for your application.
- The kVA or current rating equal to, or greater than, the rating required by the total load. It is not likely that the exact
value of the load will be found, so go to the next higher rating.
- Select the corresponding catalog number of the exact buck-boost transformer required.
- Connect the transformer in accordance with the connection diagram referenced where you selected your high voltage and low
voltage combination.
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