Omron / S8 power supplies

An S8VK-C24024 and an S8VK-G24024 have identical outputs: 240 W, 24 V, 10 A. The difference is temperature. The C is rated to 60 degrees C and the G to 70, and at the bottom end the G goes to minus 40 where the C stops at minus 25.

S8 is the Omron power supply range. DIN rail and panel mount, and the model number reads straight off the label once you know where the split is.

The number is wattage then voltage

Take S8VK-G24024.

So the last five digits split three and two. Three for the watts, two for the volts.

That is worth knowing because a 24024 does not mean 240 volts, and a quick glance can read it that way.

C or G is the decision that matters

Two supplies with the same output and very different environmental ratings.

Omron describes the S8VK-C as a light, cost effective DIN rail power supply.

Where that matters in New Zealand

A closed panel in a plant room routinely exceeds 40 degrees C inside, and an outdoor cabinet in summer sun goes further.

So a supply rated to 60 degrees may be working near its limit where one rated to 70 is not. If a panel keeps losing power supplies and the same model is fine elsewhere, measure the internal temperature before ordering another.

And the cold end matters on outdoor and cold store installations. A supply rated to minus 25 in a cool store or an unheated plant room on a frosty morning is being asked to start outside its rating.

Substituting a C for a G looks like a saving and may be the reason for a recurring failure.

They run from AC or DC

A capability that surprises people and occasionally solves a problem.

The wide AC range covers 120 V and 240 V nominal on the same unit, so one part number suits machinery built for either market.

The DC input is the interesting one. It means the supply can run from a DC bus or a battery system rather than mains, which is useful on backed-up installations and on machinery with an intermediate DC link.

Both series carry screw connections, DIN rail mounting and IP20.

The S8 families

DIN rail or panel mount is not interchangeable

S8VK is DIN rail and S8FS is panel mount. They are mechanically different.

So a plant standardising on one style needs to check what the existing panel is arranged for. A panel-mount supply does not clip onto a rail, and a rail-mount supply has no mounting feet.

The legacy families

S8VS and S8JX are the earlier generations, and they are still on plenty of New Zealand panels.

They are not the same size as the current S8VK. So replacing one with a current model may mean the adjacent components need moving, particularly in a full panel.

We supply both. On a tight panel a like-for-like used S8VS often costs less overall than the rework a current model would need.

Sizing, and why supplies fail early

Worth setting out because it is the most common reason a supply does not last.

A supply at its rating in a hot panel is a supply on borrowed time

The rated wattage assumes an ambient temperature. Above that, the usable output falls.

So a 240 W supply carrying 220 W in a 50 degree panel is not comfortably within its rating, even though the arithmetic says it is.

That is the same derating principle as the relay sockets covered on our relays and sockets page, where the socket derates to 60 percent above 40 degrees C.

If a panel is losing power supplies repeatedly, the answer is usually a bigger supply, a cooler panel, or both. Another identical unit will do the same thing.

What to check before ordering

Volt drop is worth its own note

A 24 V supply at the panel is not 24 V at the far end of a long sensor run.

Several devices on this site specify a tight supply range. The Leuze MLC light curtains, for instance, want 26.5 to 31.6 V, which a nominal 24 V supply on a long run will not reliably deliver.

So a device faulting intermittently at the end of a long cable is often a supply voltage problem rather than a device problem. Measure at the device, not at the supply.

What to send us

The full model number off the label.

Or the output voltage, wattage and mounting style, if the label has gone.

The panel temperature, if it runs hot. That decides C against G.

Whether it is DIN rail or panel mount.

Whether you need a buffer or redundancy module alongside it.

The physical space available, if you are replacing a legacy S8VS or S8JX.

What we can supply

Current production. The S8VK-C, S8VK-G, S8VK-S, S8VK-X and S8VK-T DIN rail ranges, S8FS panel mount supplies, and buffer, redundancy and DC-DC modules. Quoted with a delivered lead time.

Discontinued. S8VS, S8JX, S8TS and earlier S8 generations. Surplus and tested used, which suits a full panel where the current model does not fit the space.

Bulk. Power supplies are a maintenance store item. Send us the list.

A note on holding spares

A power supply failure takes a whole panel down, not one device.

So on a site with several identical supplies, one on the shelf covers the lot and costs very little against the downtime it prevents. They carry no configuration, so a spare is genuinely a spare.

We buy Omron power supplies

Working S8 supplies from a decommissioned panel are worth having, particularly the legacy S8VS and S8JX sizes that current models do not physically replace. See Sell To Us.

Related

Omron overview and relays and sockets.

For power supplies from other brands see Phoenix Contact QUINT and TRIO, ABB CP and Schneider Phaseo.

Send us your model numbers

The last five digits are wattage then voltage. And if a panel keeps losing supplies, tell us how hot it runs. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with OMRON Corporation. Omron is a trademark of OMRON Corporation. All trademarks, brand names and model numbers are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute electrical design advice.