Discrepancy between Schneider's calculator input and the specs given in the results.

DMSentra · Feb 24, 2019

I put in 245V input, 6.6% V change, Buck transformer, "35" for the calculate load current from kva, and no on the 50hz option. It spits out a 3S46F transformer part number, going to that page gives me a 3kva rated unit. Anyone know what gives? And, secondary voltage is listed at 16V/32V. Why???

This is the calculator page.
Buck and Boost Transformer Calculator - Schneider Electric United States

This is the Buck listing page.
3S46F - TRANSFORMER DRY 1PH 3KVA 120X240V-16/32V | Schneider Electric

Another question I just considered, for a single phase use are these a one Buck per line deal?

Strostkovy · Feb 24, 2019

The calculator gave me this one: 750SV46F
750SV46F - TRFMR DRY 1PH .75KVA 120X240V-16/32V | Schneider Electric

Either way 16V is what you need.

EDIT: Wait, you said 35kVA, not 35 Amps. The reason it gives a 3kVA unit is because the transformer is subtracting 16 volts from line, and not handling the full voltage. So 146 amps times 16 volts means the transformer only has to handle 2.3 kVA.

If it only runs on two hots it is fine with just one. If your single phase load requires a neutral then you need one on each side. If this is the case, neither transformer is the best option. Enter 120V and half of the kVA into the calculator instead and it should spit out a unit half of the size.

DMSentra · Feb 24, 2019

This runs into a self starting rotary phase converter by the way. The part about needing a neutral I'm not sure about.

Strostkovy · Feb 24, 2019

DMSentra said:
This runs into a self starting rotary phase converter by the way. The part about needing a neutral I'm not sure about.

If a neutral wire runs from the single phase panel to the RPC, then you need two half sized transformers. If there is no neutral wire then one is okay.

DMSentra · Feb 24, 2019

The situation with ground and neutral going to the same buss is what's confusing me, but I'm going to say no neutral to the RPC because of this schematic. Right???
http://www.cromanconverters.com/assets/images/converternoswitch.pdf

Strostkovy · Feb 24, 2019

DMSentra said:
The situation with ground and neutral going to the same buss is what's confusing me, but I'm going to say no neutral to the RPC because of this schematic. Right???
http://www.cromanconverters.com/assets/images/converternoswitch.pdf

That converter requires two hots and a ground, but no neutral. You are okay to use just one of the buck transformers that the calculator recommended to you.

DMSentra · Mar 9, 2019

I found out a buddy has 2 of these 2KVA B/B transformers and is willing to almost give them to me. For this volt drop I'll need a 3KVA unit for using one like I'd intended. Can I use the pair to make my situation work? That's 245V single phase out of the panel to one of these on each leg, going into the RPC at 229V, and feeding a lathe with a 33KVA max load @ 220V +/-10% rating? Again, ground and neutral are the same buss in the panel and there is no neutral wired to the RPC.

Strostkovy · Mar 9, 2019

Seems like it. Be aware that transformers do sort of have a polarity, and wiring one backwards from the other is going to burn them out, and the leads aren't marked. Easy to tell how to wire it if you pay attention though.

Search

Largest Manufacturing Technology Community on the Web

Search

Discrepancy between Schneider's calculator input and the specs given in the results.

DMSentra

Cast Iron

Strostkovy

Titanium

DMSentra

Cast Iron

Strostkovy

Titanium

DMSentra

Cast Iron

Strostkovy

Titanium

DMSentra

Cast Iron

Strostkovy

Titanium

Similar threads