An uninterruptible power supply (UPS) is an electrical device that provides emergency power to a load when the input power source, typically main power, fails.

A UPS differs from an auxiliary or emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions by supplying energy stored in batteries or large capacitors.

The on-battery runtime of most UPS sources is relatively short (only a few minutes), but is normally sufficient to start a standby power source or properly shut down the protected equipment.

A UPS also provides protection from power surges.

Care should be taken when handling a UPS as the weight can be
substantial and not uniform across the profile of the device.

All PRIMUS controllers have either an on board battery (or a small
external battery for PRI-Matic™ AB controls) to hold the program and
cycle configuration. Under most conditions, this will hold the cycle
settings during a loss of power. Depending upon the state of the
controller when the loss of power occurred, either the microprocessor
or programmable logic controller may not come up in a normal
operating condition.

PRIMUS Steam Sterilizers and UPS

A UPS is used with PRIMUS sterilizers to allow the control system to complete a cycle or “ride through” a loss of power scenario (assuming no additional power requirements are needed such as electric steam generators, vacuum pumps, etc. to complete the cycle) and allow a proper shut down to take place.

The PRIMUS UPS unit is designed to protect a single sterilizer.

A UPS is not a standard PRIMUS sterilizer component but is purchased as an option. It can be ordered from PRIMUS during the original sterilizer purchase (preferred method) or as an aftermarket component.

The PRIMUS P/N is 500308. The UPS is normally available on the shelf in the Great Bend, Kansas production inventory and can be shipped same day, if necessary.

PRIMUS UPS Parameters


Output Power Capacity300 Watts / 500 VA
Nominal Output Voltage120V
Output Frequency50/60Hz +/- 3 Hz


Nominal Input Voltage120V
Input Frequency50/60 Hz +/- 3 Hz
Input ConnectionsNEMA 5 – 15P
Cord Length1.83 meters
Input Voltage Range98 – 140V


Battery TypeMaintenance-free sealed Lead-Acid battery with suspended electrolyte. Leak proof
Typical recharge time8 hours

Runtime by Load



PRIMUS strongly recommends that only knowledgeable and qualified personnel install a UPS in the field.

The best choice for field installation is a PRIMUS Authorized Service Agent (ASA). If an ASA is not readily available to the end user, then a licensed electrical contractor or an experienced in-house electrical technician should be able to safely accomplish the job.

Each UPS comes with a detailed User’s Manual describing step-by-step how to install the UPS and who to contact at the OEM for technical assistance.


A UPS is a relatively inexpensive piece of equipment that can provide a facility insurance against potential loss of critical cycle parameters.

The above situation could happen if the controller fails in an atypical fault state which corrupts the controller’s internal memory. This will force a reload of the original factory configuration and the attendant time and hassle of reprogramming the controller with the site-specific parameters.

Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.

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