What is balanced power?
When 120-volt AC power is balanced, one side of the circuit has +60 Volts to ground while the other has -60 Volts to ground. (Across the circuit, the usual 120 Volts is still present. Fig. 1) A European 230 Volt balanced power system has +115 Volts and -115 Volts to ground on the conductors.
Standard unbalanced AC power systems have a “hot” conductor and a “neutral” conductor. In the US, the “hot” conductor nominally has 120 Volts to ground and the “neutral” conductor has 0 Volts to ground. (Fig. 2) Europe has a similar system but with 230 volts on the “hot” and 0 Volts on the “neutral.”
In a balanced power system, the voltages on the system’s two output terminals are 180 degrees out of phase to each other with respect to ground. The system reference (ground) originates at the output center tap of an AC isolation transformer. In other words, the system’s grounding reference (zero position) is located at the system’s mean voltage differential or zero crossing point of the AC sinewave. This is a far more effective way to establish a reference potential for an AC system. The center tap is then grounded to Earth for electrical safety and for referencing shields.
There is never any voltage or current present on the ground reference in a balanced power system. Transient voltages and reactive currents which normally would appear on the neutral and ground wires are also out of phase and likewise, sum to zero at the ground reference thereby canceling out AC hum and noise.
A balanced AC Power system works the same way as a balanced audio (XLR) circuit but with a higher amplitude. Both balanced audio and balanced AC incorporate phase cancellation or common mode rejection to eliminate noise.
Today Balanced Power is used in almost every high-end professional recording and production facility in the USA. Let’s be frank about this. It’s not a small difference in sound or in video quality that we’re talking about here, but rather something on the order of astonishing. Professional engineers who use balanced power routinely report an increase in dynamic range and decrease in system noise of between 16dB to 20dB. This is huge. What this means is that very subtle details that were once lost now appear in the music and in the video image that were once imperceptible. Reducing background noise enhances the clarity and resolution on both hi res audio and HD video
Mil spec oxygen free copper wire is used throughout the Model R assembly to further reduce random high frequency current distortion. This improves an already near perfect mirror image output and further widens its range of noise attenuation. The Model R’s switches and circuit breakers are the finest made and they’re duty rated for over 1/2 million operations. Every component part used in the Model R has been selected because it is the best of its kind. There is nothing that compares in quality or performance to the Model R except the Model Q.
The Model R has a simple yet elegant appearance. It features an anodized aluminum front panel that is available in black or silver. There is one blue LED indicator light above the input power switch and one above each output standby switch indicating power status at both the input and the output. The input power LED also doubles as a TVSS status light that indicates active surge protection when lit. In the rare event that it stops working and the output LED still works, this indicates that the surge protector has taken too many nuisance voltage spikes and its days are done. In the rare event that this occurs, the Model R is grounded by Faraday shields to provide excellent redundant surge protection until the TVSS module can be replaced, an inexpensive and easy thing to do.
On the rear panel, there are 12 AC outlets provided (more in the larger versions.) One GFCI outlet is independent from the front standby switch(es) and is constantly left turned on for use with components that require continuous power for a clock or to maintain volatile memory. Of the 10 remaining outlets, 6 (white) are for analog components such as amplifiers and pre amps and 4 (gray) are specially filtered outlets for digital components. A circuit breaker on the rear panel protects the system from overload and from potential short circuit fire hazards in electrical power cords and downstream connected equipment.
Model R’s are offered in 7 different sizes ranging from 1kVA to 10kVA load capacities. Most Model R’s that are rated at 2kVA or less require a 120 Volt supply circuit to operate. (The 1RE, 2RE, and 2QE require 208/240 Volts.) 3kVA and 5kVA models require a 208 or 240 Volt supply as do the 7.5kVA and 10kVA models. The chart below indicates the circuit size and standard plug type used to connect the Model R to the source power outlet.
Commercial / Industrial Applications:
Award winning Equi=Tech Wall Cabinet Systems are factory pre-assembled power distribution centers for hard wiring balanced AC power into a facility – a complete balanced power distribution system built into a wall cabinet. Only minimal installation is required eliminating many expensive hours of labor and hard to find electrical parts. All the necessary components such as transformer, breakers, GFCIs, surge protectors and line filters are factory assembled using the highest quality materials and components.
Wall systems are designed to blanket an entire facility with clean and phase coherent balanced AC power that remains stable regardless of how they are loaded down. 5, 7.5, 10, 15 and 20 kVA sizes provide 50, 75, 100, 150 or 200 amps respectively – ideal capacities for most studios and modestly sized theaters or auditoriums. These systems utilize the same precision toroid isolation transformers as Equi=Tech rack systems but they are much larger with a greater capacity. Wall systems are the easiest way to provide clean power for a larger facility, doing so with the assurance that the system will remain quiet regardless of what equipment is used or added to it at any time.
Some of the best facilities in the world run on Equi=Tech:
R Series General Specifications and Current Models:
|Model #||Load Capacity||Input Line Frequency||Line Cord Plug Chassis Inlet||Output Voltage||Circuit Breakers||# Outlet Types||Chassis Dimensions||Weight|
|1R||1000 VA||15A, 120v@60Hz||NEMA 5-15; C-14||120/60v||1-10A||(6) 15A Duplex||16.25″x14″x3.5″||48 lbs / 22 kg|
|1R/E||1000 VA||10A, 230v@50Hz||Country Specific||230/115 VAC||1-5A||(5) Universal||16.25″x14″x3.5″||50 lbs / 23 kg|
|1.5R||1.5 kVA||15A, 120v@60Hz||NEMA 5-15; C-14||120/60v||1-15A||(6) 15A Duplex||16.25″x14″x3.5″||60 lbs / 27 kg|
|2R||2 kVA||20A, 120v@60Hz||NEMA5-20; C20||120/60v||1-20A||(5) 15A Duplex||16.25″x14″x3.5″||63 lbs / 28 kg|
|(1) 20A Duplex|
|2R/E||2 kVA||10A 208/240v@||Country Specific||230/115v||1-10A||(5) Schuko Uni||16.25:x14″x3.5″||65 lbs / 30 kg|