Faq - Junlin Electric Technology

If you have questions on NVVV’s products, please read the FAQ first. If the listed answers still cannot solve your problems, ease contact us or mail us , We would reply to you as soon as received your request.

As a dedicated manufacturer of standard power supplies, NVVV provides a wide variety of power supplies to meet different demands from the markets. However, selecting the right products relies heavily on the correct electrical characteristics and specification, we listed the frequently asked questions for your reference.

What is the reason for the indicator light not turning on or flashing?

① Check whether the 220V AC input and output voltage are normal. If both the input and output voltages are normal, it means that the indicator light circuit is damaged.
② Check whether there is a short circuit phenomenon between the wiring terminal and the load.
Our power supply has a protection mechanism, and triggering overloading, overcurrent, overvoltage, and short-circuit will activate the power supply's self-protection mechanism, and the power supply will not work.

Is there any noise when the power supply is working?

① For switching power supplies with cooling fans, there will be noise generated when the fan rotates (within a reasonable range).
② Switching power supplies may make noise if the control loop oscillates.
The noise generated from the above reasons is within a reasonable range and does not affect the normal operation of the power supply.

After the power supply output is short-circuited, customers have reported that there will be current heat generation. Will the power supply be damaged if the short circuit lasts for a long time?

The common reasons for damage to switching power supplies are lightning strikes, foreign objects inside, overheating, service life, component quality issues, and other factors. This is related to the protection mode. In hiccup mode, there is no current, and in constant power and constant current modes, there is a current. Short circuit will not damage the power supply, and theoretically, short circuit for a long time in constant power and constant current modes will not damage it.

Can the input and output be connected in series or parallel?

The input can be connected in parallel, and the output can only be connected in series (the voltages are added after being connected in series). We recommend using power supplies with the same power and output voltage in series.

What should I do if the chassis is charged with static electricity? If grounding does not improve the situation, what else can be done?

① You can use plastic chassis.
② Isolate the power supply and do not touch conductive metal materials.
③ The ground needs to be effectively grounded to absorb the induced voltage.

What are the requirements for adding a switch control to the power supply before turning it on or off?

A 2P circuit breaker is recommended, as it is unknown which is the live wire and which is the neutral wire. Circuit breakers are divided into C and D series, with the D series being slow-breaking to prevent the circuit breaker from being misoperated due to excessive pulse current.

How can we solve the voltage drop problem of switching power supplies?

Reasons for voltage drop: There is internal resistance in the wire, and the voltage will be reduced when the current passes through, and the voltage at the load end will be lowered.
(1) Reduce the length of the output power supply wire, and it is recommended that the distance of the output terminal wire is within 50M;
(2) Increase the diameter of the output power supply wire, which can reduce the resistance value of the internal resistance and reduce the voltage drop;
(3) Boost the output end to replenish the voltage drop through boosting.