Hi,
What is the "transformer" for at 5:18 of this video about solar?

 

Looks like a inverter output filter inductor.

 

Hi,
What is the "transformer" for at 5:18 of this video about solar?

It's what is generally called a "voltage optimiser", and it adds or subtracts a few volts from the mains supply. It's what was previously called a buck-boost circuit, before that term was applied to switched-mode supplies.
The transformer primary is connected across the mains. The secondary (about 10V to 20V) is in series with the mains and therefore adds (or subtracts) 10V to 20V from the mains supply.
It's a con.
If he was right about it, and it was just a monitoring device, then why such a big transformer? It looks to be about 300VA.

 

It's what is generally called a "voltage optimiser", and it adds or subtracts a few volts from the mains supply. It's what was previously called a buck-boost circuit, before that term was applied to switched-mode supplies.
The transformer primary is connected across the mains. The secondary (about 10V to 20V) is in series with the mains and therefore adds (or subtracts) 10V to 20V from the mains supply.
It's a con.

Why would you need one with today's inverter electronics? To correct for wide utility voltage swings during the day.?

 

Why would you need one with today's inverter electronics? To correct for wide utility voltage swings during the day.?

Don't know. You can tell that's in Britain from the mains sockets (and his accent!) and the mains is so very rarely outside is 208V to 253V limits. Is it so they can use cheap inverters designed for a 220V supply? But his inverter is a Victron, and they are almost indestructible, and certainly compatible with British mains supply.
The "voltage optimiser" was popular a decade or so ago, before LED lighting, as it reduced the voltage to the lighting and saved a few quid off the electricity bill, Morrisons (the supermarket chain) bought a lot of them, and then when they connected their emergency lighting systems, the emergency lighting kept detecting a mains failure. Someone at their head office must have been taken in by the snake-oil salesman.

 

Don't know. You can tell that's in Britain from the mains sockets (and his accent!) and the mains is so very rarely outside is 208V to 253V limits. Is it so they can use cheap inverters designed for a 220V supply? But his inverter is a Victron, and they are almost indestructible, and certainly compatible with British mains supply.
The "voltage optimiser" was popular a decade or so ago, before LED lighting, as it reduced the voltage to the lighting and saved a few quid off the electricity bill, Morrisons (the supermarket chain) bought a lot of them, and then when they connected their emergency lighting systems, the emergency lighting kept detecting a mains failure. Someone at their head office must have been taken in by the snake-oil salesman.

I needed one on all electrical equipment while living in SE Asia in the 70's. I could time my watch using brownouts from the overloaded grid.

Some very optimistic marketing materials.
https://smartlyenergy.com/blog/how-do-voltage-optimisers-work


With a stable grid power (the vast majority of solar users), it seems totally superfluous and seems more for profit to the installer than useful for the end user.

 

I needed one on all electrical equipment while living in SE Asia in the 70's. I could time my watch using brownouts from the overloaded grid.

Some very optimistic marketing materials.
https://smartlyenergy.com/blog/how-do-voltage-optimisers-work


With a stable grid power (the vast majority of solar users), it seems totally superfluous and seems more for profit to the installer than useful for the end user.

I mainly deal with off-grid installations, but I know a very good grid-connected solar installer (he installed the panels on my house). He told me he makes a very good living from putting right early solar installations, which were done when it was heavily subsidised by the government, and every man and his dog were setting up solar installation companies, most of which went bust.

 

CONSIDER that just because somebody in a cartoon video calls something a transformer does not mean that it actually IS a transformer. Like has been mentioned it may actually be a filter to reduce and isolate the inverter switching waveform. Do not believe all that is presented on the cartoon channel!!

 

CONSIDER that just because somebody in a cartoon video calls something a transformer does not mean that it actually IS a transformer. Like has been mentioned it may actually be a filter to reduce and isolate the inverter switching waveform. Do not believe all that is presented on the cartoon channel!!

That's definitely a transformer. The only filters wound on toroids that size would be common-mode, in which case they would have windings over 180° of the core with a separator between them. Differential filters would need a gapped core, which is a lot easier to do on an EI structure than a toroid. The presenter is correct - it is "some sort of voltage optimisation device".