UPS FAQs

Q. What style of UPS should I order?

A. A UPS is designed to uphold your load upon a mains fail for a pre set length of time. Therefore, depending on the criticality of your load depends on which type of UPS you should order.

If your load is critical and any dips or spikes in the supply would cause problems with your load then Harland Simon recommends that you order a true online UPS.

If your load is somewhat sensitive to peaks and dips in the mains then you can opt for line interactive with the added buck or boost feature.

Rack mounted UPSIf your requirement is non-critical then you can opt for the offline UPS.

All of the above somewhat differ in cost and Harland Simon recommends that you spend accordingly with regards to how critical your load is.

Q. What is the difference between Static Bypass and Maintenance Bypass?

A. Static Bypass is the bypass line integral to the UPS which effectively joins the input supply to the output and continues to support the load during an internal fault.

The UPS needs to be put in to Static Bypass prior to the system being put in the maintenance bypass.

Maintenance bypass is usually a wrap around switch either of rotary or MCB design which allows the UPS to be powered down with the load powered directly from the mains whist maintenance is carried out on the UPS.

The Maintenance Bypass Switch is usually external to the UPS and incorrect operation can cause damage to the UPS therefore the UPS must always be put in to Static Bypass to operating the Manual Bypass Switch.

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Q. How do I put my UPS into Static Bypass?

A. Depending on the UPS make and model this differs so please consult the manual.

If you do not have a copy of the correct manual please contact our technical team who will be happy to help.

Q. How do I put my UPS into Manual Bypass?

A. You need to put the UPS into static bypass in accordance with the correct UPS manual before operation of the manual bypass switch, otherwise you will cause damage to the UPS.

Once the UPS has been verified that it is in the Static bypass mode you can operate the bypass switch.

Please note that in static bypass or manual bypass the load is being fed by raw mains power and any loss of power during this mode your load will not be protected.

Q. How do I know if the batteries in my system are OK?

A. Periodically UPS's do a self test on the batteries. If the batteries are not OK due to end-of-life or bad celsl the UPS will indicate this to you via an alarm.

Modern UPS's have an LCD display which enable you to see that an alarm is present and what the problem is.

Q. What is Watts per Cell?

A.Batteries used to be sized in Ah, they are now sized in Watts per cell (WPC).

This is how much load the battery can support per cell for a limited time.

Battery manufacturers provide look up charts so that when a client specifies their load in watts is required to last x minutes/hours it is easy to calculate.

Q. How often should I check my batteries?

A. Harland Simon UPS recommends that the batteries in larger systems are checked once annually by having a preventative maintenance visit.

Q. Do batteries have a shelf life?

A. Harland Simon UPS recommends that if a system is not to be put into immediate service then the batteries within the system are charged within 6 months.

If batteries are left uncharged then they begin to self discharge themselves.

Therefore after about 10-12 months the batteries if left uncharged will probably be unserviceable.

A UPS can be powered up and with the inverter left switched off.

The rectifier will then maintain batteries until the system is ready for full service.

You can also order UPS's with no batteries and order the batteries at a later date which can save money if the system is not to be put in to immediate service.

Q. Can my UPS supply a different voltage than the default setting?

A. Most UPS's can be configured either by the front panel or by software interface to supply a different voltage that what the UPS default output voltage has been set to.

This is usually around ±10-15V depending on the style of UPS.

Therefore if you have a UPS that has a default output voltage of 230VAC then you will probably be able to change it to either 220VAC or 240VAC.

Q. Can my UPS supply a different frequency than the default setting?

A. This function is only found on the Online UPS's.

So you can feed in for example 50Hz and get out 60Hz.

Most UPS's follow the frequency of the supply.

Most online UPS's can be configured, either by the front panel or by software interface so that you can get a different output frequency than that of the supply.

If your UPS is set up as a frequency converter you lose the function of the static bypass facility and upon a fault occurring the UPS will shut down and drop the load.

This is because there would be a clash of frequencies.

Q. What alarms can I get from my UPS?

A. The alarms that you can monitor from the UPS differ with the make and model of UPS.

The most common alarms are: Mains OK, Battery Low and Inverter OK.

Other alarms that are available from UPS alarm cards are as follows: Mains Fail, Bypass Active, Battery OK, UPS OK and UPS Fault, some alarm cards even come complete with a UPS Shutdown facility.

Most UPS's have an external slot where you fit the alarm card into.

The alarms are Volt Free Contacts (VFC) or Dry Contacts, which open or close upon fault depending on the make and model of UPS.

Some more modern makes of UPS come complete with alarms as standard.

Q. Can I monitor my UPS over a network?

A. Yes.

You need to fit an SNMP card into the card slot in the UPS.

This will enable you to monitor the UPS over a local network.

Instructions on how to set this up is all in the SNMP card manual.

Get in touch for help and advice in choosing your UPS.

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