# Help me to understand the outputs of this generator

This is taken from a Denyo TLW-300SSk generator. It is outputting U V W to 0 a 115V.

Is this capable of outputting 220V as well? If so, do I have to couple two phases?

• If you are getting 115V from each of U, V, and W to neutral, between each of U, V and W to another, U to V etc., you should get 200 V. If there is some means for adjusting the voltage, you could adjust for 127V line to neutral and 220 V line to line.
– user80875
Commented Mar 14, 2022 at 16:00

## 2 Answers

Electrically, the star centre has zero potential, while the potential difference between the star centre and each of the phases (and therefore the potential difference at the ends of each winding) will be 115V as shown in the diagram in the photo, so between one phase and another, for example between U and V, you should have about 230V.

If you measured the voltage between two phases you won't get 220V, you should see less volts because line voltage is phase voltage (115V/127V) multiply by square root of 3 (1.732).

• that is a three phase generator - if the phase to neutral voltage is 115, the voltage between phases will be about 195. Commented Mar 14, 2022 at 16:09
• @PeterBennett Yes I agree with you. Commented Mar 14, 2022 at 16:13
• thank you for the answer Commented Mar 14, 2022 at 17:26

Is this capable of outputting 220V as well?

It doesn't look like it from the photo. Perhaps this TLW300SS manual is helpful.

If there is only 3-phase 120VAC output, you could add a (single phase for one output) or three-phase 120V to 240V transformer for three 240V outputs*.

Keep in mind that since this transformer will be boosting the voltage by two times, any load will draw two times the primary current. Meaning, a 220V/1A device, through the transformer, would draw 120V/2A from the generator. i.e., doubling the voltage halves the available current.

*Note that the three 240V outputs would share at least one common leg between each, and their voltages are not in-phase. This means that whatever's plugged into it must not also be plugged into anything else (no "loops" back to another plug, else the following happens.) This may not be as simple as it sounds - consider if one plug was powering a plasma cutter, and another a welder. Each would work fine independently, but if both were operated simultaneously, it could spell disaster for the transformer/generator because the "hots" of both touch (the workpiece).

If so, do I have to couple two phases?

Oh gosh no, can't do that - it will damage it irreparably.

You need to consider proper Earthing, fusing, and possibly ground-fault-detection if it is not already present. Without these, the next unlucky soul to power this up and try welding and plasma-cutting with it, will be in for a very rude surprise at least.

• Thanks for your answer. i was told by the seller that this can output 220V 30A single phase. that's why i asked the question. by looking at the stickers also seems this has a 220V out but I'm confused how to get 220V 30A from this. I've added a another picture of a sticker on the generator Commented Mar 14, 2022 at 17:25
• There must either be separate generator winding(s) for the 220V circuit(s), or one or more of the "120V" phases are actually 240V center-tapped and only one half of this (120V) is exposed as 120V. You could try google translate in photo mode - it may be able to translate some of the writing. Commented Mar 14, 2022 at 18:57