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.

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.

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.

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.

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.

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.

If 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.