Home Articles Downloads Forum Products Services EBME Expo Contact
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 3 of 3 1 2 3
A
Anonymous
Unregistered
Anonymous
Unregistered
A
Hence my question:

"Does anybody know how efficient pure sinewave invertors tend to be in comparison to modified sine wave units? What capacity (Ah) battery are you using Scottish?"

D.c. connector terminations, fusing, flexibility of cables, heat-resistance/thickness of insulation, etc, etc, need to be considered carefully I reckon. As does whether earth-bonding's necessary. The inverters I've looked at are mains O/P and dc input-ground referenced.

Efficiency is quite an important issue when you're trying to give some margin for continuous operation near its limit. 1.25V O/P at 240V for a 300VA rated inverter meaning an input current of 25A off a 12V battery (assuming 100% efficiency).

Efficiency (Pout/Pin x 100%) is more likely to be nearer 80% or 90% at best I think. Hence a 12V d.c. load of ~31A at 80% with a mains load of 300VA (assuming a purely resistive load and a 240V rms sinusoidal O/P).

Last edited by Mr R J Ling; 20/06/07 3:13 PM.
Joined: May 2002
Posts: 137
Expert
Offline
Expert
Joined: May 2002
Posts: 137
We limit the current drawn from the ambulance battery to 10 amps with a fuse. (equiv. to a couple of extra headlamps) This allows the inverter to power several syringe drivers and monitors etc but will not cover more power hungry requirements such as heating elements.

Joined: Apr 2005
Posts: 96
Adept
Offline
Adept
Joined: Apr 2005
Posts: 96
The 5 trolleys we have here are all fitted with the Mascot 300W sine wave inverters Robert mentioned for two years now. We limit the equipment the number of items on the output to typically run at around half load with typical current from the 12V supply being 8 to 15 Amps (the norm usually being towards the bottom end of these figures) depending on devices running and their internal battery status.

This inverter is fitted with a 40 Amp internal fuse, therefore the cable fitted to the input is rated accordingly.


Any thoughts and opinions are purely personal & not representative of any prior, current or future employers. Any resemblance to persons living, dead or fictitious is just shear bad luck laugh
Page 3 of 3 1 2 3

Moderated by  DaveC in Oz, RoJo 

Link Copied to Clipboard
Who's Online Now
1 members (daisizhou), 435 guests, and 401 robots.
Key: Admin, Global Mod, Mod
Newest Members
MDevins, EmsR16, Fergusben1, Guilherme Gomes, Salvatore
10,173 Registered Users
Forum Statistics
Forums25
Topics11,055
Posts73,707
Members10,173
Most Online5,980
Jan 29th, 2020
Powered by UBB.threads™ PHP Forum Software 7.7.5