FUSE Question...Very Confused Please Help !

Thanks all for your responses, IT help me alot,

@ieales 

The amplifier is designed in Germany.  EU has 230V AC mains power. As stated the amplifier is made to be fed by 230V or 110V. The odd thing, at least to me, is the 110V mains feed. Not sure how the designer arrived at 110/230V.

Usually for a dual primary voltage power transformer there are two primary windings. Example 115V/230V.

The specs for the amp says it has a Max 500VA power consumption. If we assume the 500VA, is for the power transformer VA rating for the AC mains rated voltage(s), then each of the two primary windings are rated for 250VA at 115V each.

For 115V mains feed the two windings are wired in a parallel.

(2 paralleled 250VA windings = 500VA / 115V = 4.35A) 

For 230V mains the windings are wired in series.

(250VA + 250VA = 500VA / 230V = 2.2A.

 

Just a word about the amp's 250V fuse holder. Because the amp is designed to be fed from 230V mains the minimum fuse holder than can be used is the standard size 250V. So beings the same fuse holder is used also for 110V then naturally the fuse would have to be a 250 volt fuse to fit the fuse holder properly. 

.

Typical line voltage spec is ±5%. 110 x 1.05 ≈ 115. 

120v has been the US standard since 1967 🙄

120 * 1.05 = 126. 

126 volts is  ≈30% power increase into 110v transformer resistance [which will increase a little from excess power dissipation]

Check your mains voltage and get written certification from the manufacturer that the unit is 120v nominal rated. Insurance companies can be sticklers.

 

@rocky1313 The 250V thing is an arc-over rating and nothing else.

For US operation you'll want the higher amperage rating as opposed to overseas operation.

That was an (unsuccessful) attempt to be sarcastic (audiophiles often floating in higher spheres discussing effects of power cables, plugs, electrical ground, etc). 

The obvious (against sarcastic) answer is: real audiphiles replace any fuse with 6 inch nails that have been cooked in double extra virgin oil with vinigar for 2 hours and then powdered in pixel dust (the mega pixel variety). 

 

@kraftwerkturbo  Search in the Forum, a number of threads on different fuse brands; and there's no universal answer - preference

That brings up the question: which fuses sound best?

Owner manual specs: 500VA Max power consumption.

500VA / 110V = 4.55A. The designer of the amp only bumped the fuse up 110%.

4.55A X 110% = 5A. A 5A slow blow fuse seems a little tight to me for the amplifier...

500VA / 230V = 2.18A X 110% = 2.4A (Round up to 2.5A.)

 

(500VA / 120V = 4.17A X 120% = 5A)

.

You have to be careful because equipment voltage rating is different from actual wall voltage. The fuse size is determined from the transformer power rating using the equipment rating and then the wall voltage: 230V x 2.5A = 575VA Since you are using US 120 volts, the amperage is: 575VA/120V = 4.8 amps So the 5-amp fuse is correct.

what they said.

I would use the 250 volt / 5 amp fuse as the current doubles when dropping to 110. You can buy Bussman replacements on Amazon (250v/5a)- $6 bucks for a five pack. 

@rocky1313

From page 6 of owner manual:

V

S

– Mains Voltage Switch (12)

VOLTAGE SELECTOR

The Penta 5.1 amplifier can be used in all

countries and is good both for 110/115 and

220/230 V. Before the first operation, please

make sure that Mains Voltage Switch is set to

the value accepted in your country.

rocky 1313 said:

#1. AC 230:S2.5A

#2. AC 110: S5A

I have it set to #2 setting ....AC 110 : S5A .......... Correct for US.

 

 

Sounds to me like it wants you to use a different sized fuze when you switch to 110 v. This makes sense since for the same power, current doubles.

Voltage is pretty much irrelevant on a fuse so you can still use a 250v fuse in a 110 system and indeed, that seems to be what the first sentence requires.

So my thought would be to use a 250V rated fuse of 5 amp, slow blow.

Which is what is in it.

Did you blow a fuse?

Jerry

@rocky1313

Use a 250V rated fuse per the fuse holder as stated. 250V/5A

#2. AC 110: S5A... 110 is the AC Line voltage setting for the Amp when the wall outlet mains voltage is 110V - 120V. (S5A 250V fuse.)

Are you sure the fuse is a S5A? Using Google I could not find a S5A 250v fuse.

5A = 5 Amps.

S = ? Slow blow?