There will be times that you may find that the MEAN WELL power supply you need is not available within the required timeframe.

There are several reasons for this, with the two most common scenarios being a temporary stock outage of the power supply or the power supply in question being discontinued. 

In many cases there is usually an alternative MEAN WELL power supply available that will do the job. 

There are three factors that you need to consider when selecting an alternative power supply: 

• Electrical specification 
• Physical design and size 
• Special functions required 

Electrical Specifications of the Power Supply 

You need to ensure the alternative power supply can accept the incoming AC voltage and will deliver the required output voltage, or in some cases output current.  

Let us say that you want to order an HLG-150H-12, but the item is out of stock. You could easily use an HLG-240H-12 or HLG-320H-12 in its place, so long as there is space to accommodate the slightly larger sized power supplies.  

This is because with constant voltage power supplies you can use a power supply with a higher power output (WATTS) than specified. However, you cannot use a power supply with a lower power output.  

Power supplies do not ‘push’ out power. The load (the item you are powering) draws what it requires from the power supply. You need to make sure that you do not overload the power supply. Therefore, you cannot use a power supply with a lower power output. 

Constant Current Power Supplies 

With constant current power supplies and LED drivers you need to ensure that the output current is the same as specified on the power supply you originally wanted to buy.  

There is a specified voltage range within which the power supply can deliver the required output current. You need to check that output voltage range on the alternative power supply can accommodate the voltage range of the original.  

For example, the PLM-12E-350 had an output of 350mA / 22~36V. You could use the LCM-25 as an alternative because it can be set to a 350mA output / 6~54V. The 6~54V range easily accommodates the 22~36V of the PLM-12E-350.  

However, you would not be able to use the HLG-60H-C350 even though it too has a 350mA output. This is because its voltage range is 100~200V, which does not accommodate the 22~36V range of the PLM-12E-350. 

Physical Size of the Power Supply 

You need to check that the alternative power supply you are considering will fit in the space where it is to be mounted.  

This is critical if you are replacing a failed power supply inside a piece of machinery or other finished equipment.  

With DIN rail power supplies, you usually just need to check that the replacement power supply is no wider than the original, so that there is adequate room to mount it. The good news here is that many of the newer MEAN WELL DIN rail power supplies are more compact than the original models they replaced.  

The same also applies to enclosed, or caged power supplies. However, the smaller size power supply can be a problem if you want a power supply with the same dimensions so that the mounting holes in the power supply line up with those inside the equipment being repaired.  

The trick here is to look at a similar model with a higher power output. Because a power supply with a higher power output often needs to be larger, you frequently find a power supply with the exact same dimensions as the one you want to replace. Remember, you can use a power supply with a higher power output as we have mentioned above.  

Say you wanted to replace a MEAN WELL S-40-24. The closest alternative when it comes to electrical specification would be the LRS-50-24. However, it is smaller than the S-40-24, so you would need to adapt the mounting hardware so that the LRS-50-24 would fit.  

The RSP-75-24 has a much higher power output then you need, but it has the exact same dimensions as the SP-40-24, so this may be the more suitable alternative. 

Special Functions of the Power Supply 

Some power supplies may have specific features that are used in your application. 

For example, in a lighting application you may need to replace an LED driver that is being controlled by a DALI system. Therefore, your replacement LED driver must also have a DALI interface.  

Likewise, the enclosed power supply inside a piece of finished equipment may be remotely controlled. If this were the case, you would need to make sure that the replacement power supply can be controlled in the same way. For example, you may need a power supply that allowed remote adjustment of the output voltage within a range of ±10% by applying an external 0.5~5v control voltage. 

Help Identifying a Replacement Power Supply 

Please do not hesitate to contact MEAN WELL Australia if you need help in identifying a suitable replacement MEAN WELL power supply. In many cases there is another model available that will do the job.