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Selling UPS

wedgee

By wedgee,
in Sell off/Pasar Malam Shop

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wedgee Newbie

wedgee

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Hey bros just a bit of info, the UPSes i am letting go are the on-line type, with full sine wave output, not the cheap types u find at Sim Lim or even those lower end APC types...

This is the model, only diff capacity...

Please PM me for full details and price k? Collect in the east

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wedgee Newbie

wedgee

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Hey guys, a buddy of mine suggested I explain the wat the terms On-line and Sine wave outputs mean, in order to let all of u know why this UPS offers the best protection...

So here goes...

Offline UPS (Cheap $100 types which are commonly sold in retail/DIY stores):

Offline-Standby Technology

During normal operation, the power flows straight through the unit and hence only RFI filtering is usually provided. When the input voltage fails or fluctuates outside of a pre-set tolerance window, the UPS detects this and a relay will close, allowing the UPS to start feeding battery power via the inverter. The inverter is then switched on and either a square, step or sine wave form output is supplied. Upon the return of mains power, the output is switched back onto mains and the inverter is turned off. Typically there will be a break of between 4-10 ms during the transfer to and from the battery mode.

Advantages:

Low cost Silent operation when in standby Efficient

Disadvantages:

Minimal power protection - only protects against a small percentage of problems Poor output voltage regulation - fluctuations such as sags and surges will be passed straight to the load Break transfer to battery mode No failsafe - UPS will drop the load if there is a high start-up current, overload or inverter failure

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wedgee

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Line-Interactive UPS (Basic ones less than 1KVA cost abt $200 and above, popular brands are like Powerware and APC):

Line-Interactive Technology

A line-interactive UPS operates in a very similar fashion to an offline UPS, except with the advantage of better filtering and output voltage boost/reduce features. Whilst not eliminating mains-borne interference, line-interactive technologies reduce the impact of spikes, surges and sags by 'clipping' the peaks and valleys, boosting power or switching to battery back up. As with offline UPS, when the input voltage fails or fluctuates outside of a pre-set tolerance window, the UPS detects this and a relay will close allowing the UPS to start feeding battery power via the inverter. The inverter, in a good line-interactive UPS, will supply a sine wave output. Upon the return of mains power, the output is switched back onto mains and the inverter is turned off. As with offline UPS, typically there will be a break on the transfer to and from battery mode, though usually this will be shorter than with an offline UPS.

Some manufacturers will try to pass their line-interactive UPS off as online models by calling them 'digital online', 'inline' or 'online interactive' - make sure you know what technology the UPS you are buying actually uses.

Advantages:

Lower cost than online Gives better protection than offline Silent operation when in standby Efficient

Disadvantages:

Fluctuations, such as spikes, can still be passed straight to the load Break on transfer to battery mode. No failsafe - UPS will drop the load if there is a high start-up current, overload or inverter failure

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Online UPS (Less than 1KVA goin at $350 onwards, most popular with people who value their equipment, and in our case, their precious livestock!):

Online Double Conversion Technology

An uninterruptible power supply using true online double conversion technology provides the highest level of power protection available. The UPS converts the 230V input AC mains supply to DC power, which is then used to charge the battery. The DC current flow is then fed through an inverter stage that reconstructs the 230V AC mains output. Because the AC output is completely regenerated, it will be completely free from any mains-borne interference such as spikes and voltage variations. The output voltage and frequency is controlled precisely, thus ensuring a clean and stable sine wave power output. Online UPS are able to withstand large fluctuations on the input voltage before transferring to battery power (typically 276V-184V) thus eliminating unnecessary battery discharges. Upon mains failure, transfer to battery power is seamless - no break. Online UPS also have various failsafe and self-diagnostic features that will instantly transfer the load onto mains power if there is a failure within the UPS hardware, or if the UPS is overloaded.

Advantages:

Continuous & total power conditioning Failsafe/overload protection with static bypass facility No break on mains failure Wide input voltage tolerance Recommended with Generator sets

Disadvantages:

Because of the technology used online usually cost's more than other types of UPS technology

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As for Sine wave Output (From almost all Online UPSes):

My own interpretation - Full sine wave outputs from UPSes are identical or some say even cleaner than utility power, as it is filtered and free from spikes and distortion. These allow yr equipment, esp motor and transformer loads to last longer and build up less heat...Aquarium pumps belong to motor loads, which are critical when power trips or failures occur in yr estate.

And Stepped Wave outputs (Commonly used in mid-range UPSes tat backup office PCs):

My version - Lookin like a pyramid waveform, unlike the smooth curves of a sine wave, these are suitable for use on normal office equipments and most appliances. There is a tendency for the stepping up and down 'spikes' on the waveform to cause heating on motors, thus reducing their lifespan. Some reefers even noted some difficulty in using their Tunze streams on these types of outputs...

OK, hope that all these helped. :rolleyes:

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