Question UPS nJoy Cadu vs Kraft&Dele,which is better?

[ghost86]

I want to buy a 2000vA uninterruptible UPS power supply. The budget I have, is a maximum of 120$. I have never had anything like this ,and I would also have some questions about it. Those who own such tools like this:

1. Kraft&Dele and nJOY are good in this segment? I ask about them because I fit in the budget I have.

2. Some UPS state they tell have an automatic restart function, while others, do not specify this. My question would be if they all have this function, even if it is not specified in the product description?This aspect is very important to me.

3.between nJOY Cadu and Kraft&Dele what is is the best option?

4. and the last question, even if it has nothing to do with my budget, but to keep in mind for future. What is the difference between UPS with PURE Sinusoidal and the cheapest ones with simulated sinusoidal, and why UPS with pure sinusoidal cost twice as much? What makes this pure sinusoidal?

thank you,

https://i.postimg.cc/vZXZkLh0/ups.jpg

 

[bill001g]

These are not well known brands but it may just be not well known in english speaking countries.

BUT based on your last question you might not want either. It depends on what you are going to protect with these.

What you find lately is power supplies for computers and some other devices have become extremely efficient. This is the so called 80plus ratings you see on power supplies. The power supplies are very dependent on the sign wave being of very good quality to make these work. The simulated sign wave if you look up the photos of that compare them you will see has lots of spikes and flats in the graph. Using these can cause the power supply to not be able to produce the maximum power it can and in worse case it can cause damage to the power supply. Some power supplies in computers will turn off if the power is not of good enough quality to protect themselves.

This is mostly desktop computers but even some laptop and fancy tv or monitors power blocks can be affected.

Not sure a lot of people use non sine wave UPS on computers because they don't know any better. You are generally not running on UPS for that many minutes total in a year so it is hard to say how much damage it does. The power supplies do not explode or something. It likely just reduced the life span of the power supply.

In any case it is not recommended to run a modern computer on a simulated sine wave UPS...and even more so on say a generator.

 

[arif1752002m4a1]

I want to buy a 2000vA uninterruptible UPS power supply. The budget I have, is a maximum of 120$. I have never had anything like this ,and I would also have some questions about it. Those who own such tools like this:

1. Kraft&Dele and nJOY are good in this segment? I ask about them because I fit in the budget I have.

2. Some UPS state they tell have an automatic restart function, while others, do not specify this. My question would be if they all have this function, even if it is not specified in the product description?This aspect is very important to me.

3.between nJOY Cadu and Kraft&Dele what is is the best option?

4. and the last question, even if it has nothing to do with my budget, but to keep in mind for future. What is the difference between UPS with PURE Sinusoidal and the cheapest ones with simulated sinusoidal, and why UPS with pure sinusoidal cost twice as much? What makes this pure sinusoidal?

thank you,

https://i.postimg.cc/vZXZkLh0/ups.jpg

I never used both of these brands.... But as I have Studied and worked a lot on Power Electronics... And after looking at their Specifications..

What I can say is.. nJoy is more promising..
+ it's change over fast during AC failure...
+it is Pure sinewave Inverter Design.. Probably H-Bridge Circuit.
+it has more features compared to Kraft and dele...
+ Narrow Voltage range.. which is in my views very good... For PCs..
+More Safety Features too...

Coming to 2nd Question..
What is automatically Restart feature...

So When UPS is Fully charged... and During Power loss... It powers your PC..and after sometime. It's battery dies... and UPS shuts down...

If your UPS have No automatic Reset/restart mode... After Mains in on.. It will not turn on by itself.. unless you press the power button...

If your UPS have Automatic Reset/restart mode..
After mains is on.. UPS output will be on.. (if Ups is on)..


Last Question..

Modified Sinewave inverters actually uses H-Bridge Inverter.. Which let's current flow in one direction for (12ms in one direction and open circuit for 4ms and again let's current flow in reverse direction for 12ms and open circuit for 4ms again) what is does it creates periodic Square wave signals.. with dead time (that 4ms time)... On paper. It's RMS value is equal to RMS of AC Sinewave.. but..
+In general Modified Sinewave inverters are Slow in detection of AC failure.. so they starts after like 20-30ms after AC fails.... They are simple to build.. can have more features... But...
+They creates very high voltage spikes under no load on output. Like close to 400 voltage peaks.. which is very dangerous...
+They creates a loud humming like sound.
+They are more prone to fail.. due to larger current spikes on MosFETs...

Sinewave inverters on the other hand... Do this same... But with rapid on and off MosFETs.. and Yes with Variable dead time...
Their operation frequency goes upto 200Khz. For faster response time.. and low change over time...

They are More safer.. efficient and Reliable than modified sinewave inverters..

They produces no buzzing sound, no high voltage spikes during operation etc etc..

So always for for pure sinewave inverters.. ✌🏼

 

[bill001g]

What I can say is.. nJoy is more promising..
+ it's change over fast during AC failure...
+it is Pure sinewave Inverter Design.. Probably H-Bridge Circuit.

Not sure what you were looking at. nJoy has many UPS some which are pure sinewave but the Cadu line appears to be their low end models and says it is simulated sine wave

 

[arif1752002m4a1]

Not sure what you were looking at. nJoy has many UPS some which are pure sinewave but the Cadu line appears to be their low end models and says it is simulated sine wave

S... cadu 2000 is actually Modified Sinewave inverter based UPS... But still not bad for its price... But as i said. I never used Njoy ups ever.. can't sat anything.. but specs sheets still looks promising.. and internal pics too ..

 

[DSzymborski]

Can't say about nJoy specifically about UPS, but given their behavior in power supply issues in the past, I would never buy anything from them, especially something that's safety equipment. The used to print fake 80 Plus labels on their PSUs and when caught doing that, they started assigning themselves their own labels that simply look sort of like them. Their PSUs were cheap and full of junk parts, ripping off mostly Romanian customers, and I wouldn't trust their UPS unless someone reputable really tore one them apart and looked at the components.