CyberPower PR750LCDRM1U – UPS Review

When I lived in California, noisy, unstable power and loss of power was never an issue for my home theatre. However, after moving to New Jersey loss of power and unstable voltage has been a regular event. So, as I have always used a bulb projector I installed an uninterruptible power supply (UPS) in order to protect the bulb and allow it to cool down when mains AC power was lost. This UPS was ONLY to protect the projector bulb but I took the liberty of also protecting the video processor and panamorphic lens controller. The UPS selected was a CyberPower OR700LCDRM1U that digitally generates a simulated sine-wave when AC power is lost, and with a transfer speed of only 4ms, (0.004secs), their is no disruption to the projectors image. This supply is line-interactive so can make small corrections to the AC voltage without using its battery and when the voltage is stable it will bypass all its electronics, so it is considered to be “Green” as in this mode it uses very little power. To date I have been very pleased with its performance and it has never let me down. I have had to replace its batteries twice in ten years, a normal requirement. 

That brings me to the CyberPower PR750LCDRM1U UPS. After various upgrades to my HT rack equipment it became necessary to power up and shut down some of the equipment in an orderly sequence so as not to damage any of my four subs. Loss of power to the AVR immediately mutes its outputs and when power returns it will always come up in standby mode with all satellite speaker outputs muted.

Household AC main power looks like an analog sine wave. For those not aware of it there are two basic types of UPS AC power output waveforms, Sine Wave and Simulated Sine Wave.

Sine Wave

Simulated Sine Wave

Waveform Comparison

Some equipment, particularly that listed as having ENERGY STAR or 80PLUS standards incorporate Active Power Factor Correction (Active PFC). Devices with Active PFC power supplies often require sine wave AC power for guaranteed trouble-free operation. This requirement is can be an issue for PC computers, Apple iMAC’s, servers and some monitors, so be warned. 

Most HT equipment will accept simulated sine wave AC power. Remember that your HT equipment is only going to run on the UPS for a few minutes while you safely close everything down, wait a couple of minutes for the power to return, or wait for your house generator power. 

So why the did I choose a sine wave UPS to run my HT rack equipment, especially as they cost up to two times the price of the equivalent simulated sine wave UPS that I was using for my projector etc.? My rack contains over $20,000.00 in equipment, so I was being very cautious to use the “cleanest” UPS that I could and supplying a “square wave” simulated sine wave was not part of that strategy. Also due to a shortage of rack space the UPS could only be 1RU high, another increase in cost as desktop and stand alone units are less expensive. 

I run the following HT rack equipment of the PR750LCDRM1U UPS:

• Denon A1 – 120v x 2amp=240watts
• Denon A100 – 55 watts
• Oppo 103 – 35watts
• Oppo 203 – 40watts
• Oppo 205 – 65watts
• Analog PSU 1 – 10watts
• Analog PSU 2 – 15watts
• Analog PSU 3 – 20watts
• Sub Digital Delay – 12watts
• L/C/R Analog Equalizers – 18watts
• Voltage Amps – 12watts

Rack mount this UPS with care as it weighs 40lbs. I would not rely just on the racks front ears for all of its support, its rear really should be supported. Once installed I left the UPS for 24hours to allow the batteries to fully charge. This UPS also has a very fast transfer time of 4mS (0.004 secs). This is so fast that the residual stored energy in each of the HT equipments power supplies can “bridge” the 4mS outage without impacting their performance, turning off or causing any pops or clicks. 

I setup my scope to look at the output waveform, turned my HT system on, placed a Blu-ray on the Oppo 205 and with baited breath I asked my daughter to throw the appropriate breaker. All was just as I expected, the UPS AC sine waveform looked very similar to the house main AC supply, the output voltage showed 120volts and the indicated run-time was 11 minutes.

Image Credit: CyberPower

More importantly the system carried on as if nothing had happened. Turning the breaker back on returned to running off main AC power without any glitches. 

This UPS is also line interactive and features automatic voltage regulation (AVR), meaning that it will correct for small changes in the incoming AC line voltage without using the batteries. The AVR will correct if the ac line voltage falls below 80volts or exceeds 150volts, representing a boost +30% and boost +14%/buck -12%. Unfortunately I am unable to test this as I have no suitable autotransformer to adjust my incoming AC line voltage. 

This UPS, like most others, can be remotely monitored and controlled via network (option), USB or serially with free software loaded onto a PC. I find that the lit front panel on/off power switch, LCD display and its associated button are sufficient for my day to day use.

LCD Status Display:

• AC Power
• Current/Load Level
• Runtime
• Battery Level
• Battery In Use
• Input Voltage
• Output Voltage
• Overload
• Silent Mode
• Normal Mode

The LCD display and button may also be used to setup some of the UPS basic operating parameters:

For most of us there will be no need to alter the manufacturers UPS Setup defaults. 

If you find the alarm beeping annoying during power loss, holding the display button for 4 seconds will mute it. For those with other AC supply requirements, 2 of the rear outlets can be programmed to stay on longer than the other 4, thereby allowing load shedding and letting the UPS support those two outlets for an increased period. The rear panel also has an overload circuit breaker, a red fault LED that indicates if your wiring has an error and an RJ11 connector that can be wired for emergency power off.

Some EMI/RF filtering is included as is 1,780joules of surge suppression. 

Since the installation a few weeks ago we have already had three power outages that lasted more than 1 hour so it is continuing to earn its keep. 

Basic Specifications: PR750LCDRM1U

• VA: 750VA
• Watts: 560w
• Transfer Time: 4mS
• Automatic Voltage Regulation:  Boost 1 +30%, Boost 2 +14% / Buck -12%
• On Battery Voltage: 120VAC +-5%
• On Battery Frequency: 50/60Hz +-1%
• Outlets x6: NEMA 5-15R
• Runtime Full Load: 7 minutes
• Runtime Half Load: 23 minutes
• Batteries x4: Replaceable 6V/9Ah Lead Acid
• Overload Protection: Internal Circuitry Limiting and Circuit Breaker

Warranty:

• Supply and batteries: 3 years
• Attached equipment insurance against damage due to UPS failure: $400,000.00

MSRP:

• PR750LCDRM1U: $469.00
• OR700LCDRM1U: $329.95

If you are looking for a rack mounted UPS, both of the above uninterruptible power supplies are highly recommended.

For more information on UPS requirements see this post: UPS – An Introduction

For more technical information on uninterruptible power supplies visit CyberPower.