Cold-Start Power Supply Requirements: Specify the First Power-On

Describe the first power-on after a cold shutdown

For equipment that may be switched off in an unheated location, a purchasing brief should describe the next startup as well as normal operation. Ask what temperature the power supply may reach before input power is applied, what the equipment demands immediately afterward, and what a successful start looks like.

Do not treat a country name as the temperature requirement. An indoor installation in Canada and an unheated installation elsewhere can need different review conditions. Have the equipment team specify the actual environment and installation arrangement.

This guide is a procurement planning aid. It does not establish a cold-start rating for any Voltivo Power model or authorize operation outside a product's confirmed limits.

Why startup deserves an explicit question

TDK-Lambda discusses cold startup in supplies using inrush thermistors. In those designs, a cold thermistor has higher resistance and warms during operation. At very low temperatures, a supply without the relevant startup rating may repeatedly attempt to start or fail to start; load and input conditions matter.

This is a design-specific explanation, not a rule that every supply behaves identically. Ask the supplier whether its stated temperature range covers the requested startup conditions and request the supporting conditions or evidence. Do not copy the reference article's temperatures or load percentages into another model's specification.

Provide a startup scenario, not just a temperature range

Unpowered condition

Describe where the equipment is installed and the expected temperature before startup. Have engineering define the conditioning needed for evaluation.

Input at startup

Provide the required AC input conditions and identify any different conditions across the intended markets.

Load sequence

List which circuits and accessories are active immediately and which turn on later. Supply engineering estimates or measurements and label them accordingly.

Startup outcome

Define acceptable time to readiness, required output behavior and whether repeated attempts or an operator reset are acceptable.

Configuration

Identify the equipment variant, supply model under review, output, cable, enclosure and installation arrangement.

Keep cold startup, operation after warm-up, and unpowered storage as separate questions in the comparison sheet. Ask the supplier to map each answer to the relevant document rather than accepting one general “wide temperature” statement for all three.

Compare proposals against the same scenario

Imagine a terminal that remains off overnight and powers several accessories when switched on. This is an illustrative planning scenario. Purchasing should ask the engineer whether all accessories must start together and record the agreed sequence. A demonstration with accessories disconnected does not resolve the request for the complete configuration.

Send that same scenario to each supplier. Track the response as documented coverage, additional evaluation needed, or an explicit exception. A supplier's report may be useful without covering every requested condition; record what is missing so it remains visible when comparing price and lead time.

If a proposal requires a different startup sequence or installation arrangement, send that change back to the equipment team. Purchasing should not silently revise the application to make the quotation appear compliant.

Agree the evaluation before releasing the order

Have the responsible engineer define the conditioning, input and load combinations, number of starts, measurements and acceptance criteria. Ask for a report that identifies the sample and configuration, along with the conditions actually evaluated. Keep a typical demonstration result separate from a supplier's stated operating commitment.

Once the configuration is accepted, reference the agreed startup requirement and evidence in the approval package. Reopen the review when an equipment variant adds a load or changes the startup sequence. This makes a repeat order traceable to an actual application decision.

For a Voltivo Power inquiry, share the output requirements, expected startup environment, load sequence, installation details, destination markets and quantity. Cold-start suitability and available documentation must be confirmed for the proposed model and configuration.