Re: Step-down Transformer, AVR thread (and Variac)

Sorry. Should've been more specific. The Bosch4100 TS is 15A so at 110V, that should be roughly 1.7kW. You mentioned derating by 60%, so should I be getting a step-down at 1kW? Add some headroom, should I get 1.5kW? Which brand/model would you recommend at this capacity?

Thanks!

Oh no! If the tool draws 1,700 Watts, then you should get a 2500 Watt (by my estimate) transformer. Transformer capacity should always be bigger than the load. Too bad that i'll be the bearer of bad news, but it's a considerable expense...

Funny thing is, time factors big on this- how much time vis-a-vis current overload it'll take to get the thermal mass going and heat up to become chernobyl. (It's very exponential.) ...If it gets periods of rests, you can even overload it to some extent. (An arc welder behaves like this too.) So....

...I really like to have a comfy safety margin, specially since it's electrical so i'd prefer to get a 3000 watter... but they're really expensive ...but i don't want to fry myself... ...but no one uses a TS for more than 10 minutes at a time... ...hmmm.... a 2000 watter will do for non-continuous use of a 1700 watt load.

Re: Step-down Transformer, AVR thread (and Variac)

Will probably go for a 2kW step-down. I imagine the cost difference going up is not linear so anything larger would be terribly expensive. Thanks.

Re: Step-down Transformer, AVR thread (and Variac)

Will probably go for a 2kW step-down. I imagine the cost difference going up is not linear so anything larger would be terribly expensive. Thanks.

I searched for automatic voltage regulators and step-down xformers in sulit.com.ph. I was surprised to find out that AVRs are cheaper than plain transformers. I settled for this seller.

http://www.sulit.com.ph/index.php/view+classifieds/id/1857891/Automatic+Voltage+Regulator+and+Stabilizer+%28Servo+Motor+Control+%29?referralKeywords=automatic+voltage+regulator

Bought the 3kW Samwon. The build looks solid. Been using it for a month now (weekends only) and ok pa naman siya.

Malapit ka lang naman yata sa amin, you can drop by and try it out if you want to.

Re: Step-down Transformer, AVR thread (and Variac)

Looks to me like those are real good prices for an AVR.

Re: Step-down Transformer, AVR thread (and Variac)

Malapit ka lang naman yata sa amin, you can drop by and try it out if you want to.

thanks! Will PM you later.

Re: Step-down Transformer, AVR thread (and Variac)

For motors with 1700W load rating, better go with a 3000W AVR/step down transformer. Motors consume more current during startups.

Re: Step-down Transformer, AVR thread (and Variac)

Bought the 3kW Samwon. The build looks solid. Been using it for a month now (weekends only) and ok pa naman

instead of PMing you, thought I'd post my question so others may benefit from your response.

Why did you get the Samwon as opposed to the Sig and Goldsource?
What do you use the AVR on?

Thanks.

Re: Step-down Transformer, AVR thread (and Variac)

First I wanted the Sieg because it sounded German/Russian. The other two sounded Chiwanese. :p

But the seller recommended Samwon. Wala pa daw silang warranty claim for that brand.

I use it to power an 11-amp router and a 15-amp circular saw. Pero hindi sabay. 🙂

Also, highly recommended in the pinoy dvd forum is the Yaden brand. Kaso the 2kW
costs 5K sa Armstrong sa Raon.

Re: Step-down Transformer, AVR thread (and Variac)

Thanks. That info was very helpful. I will be running a 15A TS on my step-down so it is comforting to know that your Samwon works.

Re: Step-down Transformer, AVR thread (and Variac)

Thanks. That info was very helpful. I will be running a 15A TS on my step-down so it is comforting to know that your Samwon works.

No problemo. Correction nga pala... its a 15-amp nail-cutter. :p

Re: Step-down Transformer, AVR thread (and Variac)

Got this in PEX:

"The AVR is typically used for critical appliances sensitive to voltage fluctuations. Typically, the power from our outlet is NOT constant 220Volts. So the AVR is there in order to cope with the varying voltage. That's why AVR is used mainly for electronics like PCs, Components, and the like.

Now, for Step-Down Transformers. . . it has NO regulator function. It is mainly used for its step-down function. . . You plug it into 220Volts, it would output 110Volts. Now if the supply voltage varies, the output would also vary."

So what do we really need?

Re: Step-down Transformer, AVR thread (and Variac)

Step-down lang pwede na. The tools can handle momentary fluctuations.

In this case I got the AVR because its cheaper.

Re: Step-down Transformer, AVR thread (and Variac)

Another feature I like in the Stac AVRs is a very efficient fuse based tripping system.

Overload protection et al..... Once my 110V chopsaw was accidentally plugged to the 220V output and the fuse just gave in. No harm done to the saw.

I always prefer AVR so as to have regulated voltage. Here in Pasay the Meralco supply fluctuates up to as low as 185-190V.

Re: Step-down Transformer, AVR thread (and Variac)

My 3kW Samwon AVR burned out yesterday!

Was doing what I regularly did: ripping wood. Smelled something funny and thought I was feeding wood too slow that it may be burning. Fed it a little faster but still smelled funny so I stopped. I then noticed smoke from the AVR.

Darned Sulit website is now inactive but still managed to trace the phone number of the seller. Seller was difficult to talk to. One of those guys who likes to talk and never listens. Immediately concluded I overloaded the AVR without even asking about circumstances.

After persistently completing my sentences (while he persistently tried to cut me off), he then conceded that he has a 6month warranty and advised me to look for my receipt.

Darned if I'll find the receipt. And I'm pretty sure it's more than 6 months.

Will still try to get it replaced.

Re: Step-down Transformer, AVR thread (and Variac)

Ding must you get a replacement, I highly recommend getting a 2kw (Minimum) step-down transformer. an AVR just doesn't cut it for machines, they do work well with electronics but not motors because of the load of the initial start. the draw often adjusts the avr to compensate and when the load drops from the initial start you have a voltage overload until it regulates itself again. the constant changes alone will bring your avr down fast. I do have several AVR's several Zebra's and a Stavol, none of which powers my tools.... hope this helps you spend more :surfing: