Why is the maximum permissible value for LTV 208V and can it be increased?
In the UK, the acceptable range is 230V -6% +10%. That gives 216V as the minimum. It looks like the UPS could therefore transfer an out-of-spec voltage to equipment?
The SMT1500i is a 230v UPS. It uses boost and trim voltage regulation to give a wide range of acceptable input voltage. At default settings the input voltage range is 160 - 286V, and at the widest settings it would be 151 - 302V.
The issue isn't the input voltage but rather the output.
When set at 230V, the narrowest output range before AVR activates is 208 - 253V; when set at 240V, the said range is 216 - 264V. In both cases, the voltage is outside the UK tolerable limits of 216.2 - 253V.
Hi Billy -
The unit can boost voltage by either 6% or 12 % or trim by 6%. If you have the unit configured for 240v you will generally be +/- 6%. If you need a narrower range of output voltage, you can tighten your high or low voltage transfer points. If you application requires a a higher degree of voltage regulation you could go with an Online UPS such as the SRT product line. The SRT units will typically be +/-1%.
The unit will boost or trim only when it reaches either high or low voltage transfer points, right? But you cannot tighten the high/low points below +/-10%. That's fine for EU, but not for Old Blighty.
I don't have an international unit here to check at 240v output, but at the standard 230v output your settings are:
Is your issue the specific load you are attaching or a standard that is specific to the UK? I have never heard of any problems using SMT series products in the UK before, but I mostly support customers in North America. You may be best served by contacting your local tech support team for details that are specific to your location.
Ok, thanks for your help.
The issue is a standard specific to the UK: 27. (3) (b) of the The Electricity Safety, Quality and Continuity Regulations 2002 which defines -6%/+10% for the supply voltage.
It's mostly academic to be fair, as nearly all equipment will be made to handle 208V for the EU market, but I'm still surprised the option for UK tolerances isn't there.
The SMT1500i defaults to 230v, but can also be configured for 220v or 240v. In any of these 3 settings your output would be within that +/- 6% tolerance. This unit does not have a 208v mode, so that would account for not being within tolerances with a 208v supply. If you need a 208v solution your closest option would be the SMX2200HV.
Hope this helps
I'm not seeking 208V thanks. That's simply the minimum voltage that can be legally supplied, and that equipment should be tested to, in the rest of the EU (230V -10%).
I was hoping the unit could clamp my output voltage to within UK spec, but it can't. It can only do +/- 10%. I'm very happy with the unit otherwise.
Choose a location