5 Year Limited Warranty
On Sure-Volt and Mini-EVR Models
The Problem with Electronic Voltage Regulators
Electronic tap switching voltage regulators (EVR) have always had a common problem: applications with high inrush or overload currents (like motors and transformers) causing the electronic switches to fail prematurely, often within a matter of days or weeks. The electronic switches (Silicon Controlled Rectifier semiconductors or, simply SCRs) fail because they are placed directly in the load current path where they are subjected to over-currents and overheating each time the load equipment demands extra current. Using SCRs with higher current ratings and/or cooling fans does not prevent the SCRs from being stressed by over-current or overheating – it simply increases the number of times the SCRs can be operated beyond their capacity before they fail.
You can see the problem right in the product specifications. The overload capacity of the typical EVR (and UPS) will be something like 1000% for 1 cycle and 200% for 10 seconds. This is the overload rating of the SCRs or other power semiconductors. Contrast that to 1000% for 1 second (60 cycles = 1 second), the typical overload rating of a transformer.
To make a bad problem worse, the failure of an SCR in an electronic tap switching voltage regulator can damage other components in the unit, like the transformer. A damaged transformer usually means replacement of the entire EVR.
The Solution
The Sure-Volt and Mini-EVR electronic voltage regulators are made to handle the high inrush and overload currents found in medical imaging, manufacturing, processing, municipal services and many other applications. By isolating the SCRs from the load current path, the Sure-Volt and Mini-EVR eliminate the cause of SCR over-current and overheating. This isolation means that the SCRs are never subjected to any inrush or overload currents - even short circuit currents.
This is also the reason that the Sure-Volt and Mini-EVR have an overload rating of 6000% for 1 cycle, 1000% for 1 second and 500% for 5 seconds - built for the toughest inrush and overload applications.
Confidence
More than hundred million SCR service hours and zero failures in some of the toughest applications like, MRIs, CNC machining, oil rigs, steel and paper mills and refineries, is enough to make us confident that the Sure-Volt and Mini-EVR have the “right stuff”.
To make our point about the reliability of the Sure-Volt and Mini-EVR, we offer an industry-exclusive 5 year limited warranty against SCR failure and other component damage (including the transformer) caused by an SCR failure. See the details below.
5 Year Limited Warranty
UST extends its standard warranty period for Silicon Controlled Rectifiers (“SCRs”) to five years. UST warrants to the purchaser named on the original product warranty registration for a UST Sure-Volt™ or Mini-EVR™ power conditioner purchased after May 15, 2008, to supply replacements for any SCR in the power conditioner that fails in normal operation (when properly maintained) at no charge within sixty (60) months from the original date of shipment of the power conditioner from UST. UST’s standard terms and conditions will continue to apply. UST will pay postage or freight on the replacement parts only to addresses within the U.S.A.
If within sixty (60) months from the original date that a Sure-Volt™ or Mini-EVR™ power conditioner is shipped from UST, a failure of an SCR damages another component in the same power conditioner, when normally operated and properly maintained, the purchaser named on the original product warranty registration may return the power conditioner to UST for repair or replacement (at UST’s option) of such damaged component. Purchaser will be responsible for the shipping costs.
The above two paragraphs express the exclusive warranties and remedies pertaining to or arising from SCR failures under normal operation, are not assignable, and do not include failures or damages that arise from acts of God.
Read more about other advantages of the Sure-Volt and Mini-EVR power conditioners…