If you’re reading this, chances are you’ve got a few low-voltage VFDs sitting in your warehouse right now, or maybe you’ve got a shipment coming in and you’re wondering, “Wait, can these just be stacked on a pallet and left in the corner?” Let me be real here— I’ve seen it all. Over my 8 years as part of a low-voltage VFD supply team (I’m the guy who gets the frantic 2AM texts when a shipment’s damaged before it even hits the client), I can’t tell you how many times we’ve had to turn away a unit that was “stored fine, right?” only to find corrosion, fried circuit boards, or dead capacitors that cost us thousands in replacements and pissed off a client who needed their system up and running yesterday. Low Voltage VFD
Low-voltage VFDs (that’s variable frequency drives, for anyone who’s new to this game) are tough pieces of equipment, but they’re not indestructible. The ones we ship every day are built to handle factory floors, dusty warehouses, and fluctuating power, but when they’re just sitting in storage? That’s when things go sideways. I once watched a client store a batch of 15 230V VFDs in an unheated outdoor shed in the middle of winter— by the time they called us 3 months later, every single one had condensation buildup that corroded the input terminals. They tried to argue it was our “bad quality control” until I showed them the photos of their shed with a hole in the roof and snow piles leaning against the wall. Lesson learned: storage isn’t just “put it somewhere out of the way.” It’s a make-or-break step that keeps your VFDs working when you need them.
First off, let’s nail down the basics: what even makes low-voltage VFDs tricky to store? Unlike a simple motor or a wire, these have sensitive electronic components— circuit boards, capacitors, microprocessors, even tiny sensors that tune the drive to your system. Those parts hate extreme temperatures, moisture, dust, and even old age (yes, electronics have a shelf life if they’re not cared for). Capacitors, for example, start to degrade after about 5 years, but that number plummets if they’re exposed to high heat or humidity. We’ve had units come back that were stored for 1 year in a hot, humid space that had capacitor leakage— something that would never happen to a unit kept properly.
Now, let’s break down the actual storage steps, the stuff that actually works and that we’ve tested hundreds of times here at our shop. I’m gonna make this practical, no fancy jargon, just what you need to do.
First, pick the right storage space. This is non-negotiable. I don’t care if you have a $10,000 warehouse or a closet in your office— as long as you hit these marks. Temperature is the big one. Low-voltage VFDs like it between 10°C (50°F) and 35°C (95°F). Avoid anything below freezing or over 40°C (104°F) if you can. Freezing is bad because moisture in the air turns to ice, and when it thaws, that’s condensation eating away at metal parts. High heat? It speeds up that capacitor degradation I was talking about— we’ve seen a unit stored at 45°C (113°F) for 6 months lose 20% of its capacitance, which makes it useless for startup.
Then humidity. Keep it between 40% and 60% RH (relative humidity). Anything above 65% is a breeding ground for mold and corrosion, anything below 20% can cause static electricity— and static is the #1 silent killer of circuit boards. You wouldn’t believe how many drives we get that have a tiny static burn mark on the circuit board that no one notices until you turn it on, and then it just dies. If your storage space is too humid, get a cheap dehumidifier (they’re like $50 at Home Depot, way cheaper than a $2,000 VFD replacement). If it’s too dry, a small humidifier or even a bowl of water in the corner works, just make sure it’s not sitting right on top of a pallet of drives.
Also, skip the dusty areas. If your storage space is next to a loading dock where dust and dirt blow in, or near a construction site, cover the drives with a plastic sheet or put them in their original packaging. Wait— speaking of original packaging: that stuff is not just for shipping. The antistatic foam, the plastic wrapping, the cardboard boxes? They’re designed to protect the VFD from exactly the stuff that’s bad for storage. Don’t throw it away after unpacking the first unit. I’ve seen clients do that all the time, and then when they need to store the rest, they’re stuck using garbage bags that don’t stop moisture or static.
Next, how to handle the physical storage of the drives themselves. Stacking is a big no-no. Sure, it might save space, but if you stack a 50lb VFD on top of another one, you can crack the casing, bend the terminals, or even damage the internal circuit boards. We always recommend storing drives upright, exactly how they’re meant to be installed. The original box usually has an arrow on it showing the upright direction— follow that. If you don’t have the box, just look at the drive itself: there’s usually a raised section on the bottom meant for mounting, so set that on the floor, not the top.
Also, don’t store anything heavy on top of the boxes. No pallets of parts, no tools, no empty boxes. A friend of mine who runs a manufacturing plant stacked 10 pallets of gear on top of a stack of VFD boxes, and when they finally took the top layer off, half the boxes had crumpled corners and one drive’s casing was cracked. That was $3,500 down the drain because someone was in a hurry.
Wait, another thing: if you’re storing drives for more than 6 months, you need to do a periodic check. I can’t tell you how many people store a drive for a year, then pull it out and plug it in, only to have it blow up on startup. Here’s the deal: even when a drive is turned off, it’s still a tiny electronic device that drains its battery (yes, drives have small internal batteries that keep settings and charge capacitors). Every 3 to 6 months, depending on the temperature, you should power the drive on for 1 to 2 hours. Not full load, just plug it into a standard power outlet (as long as it’s the same voltage as the drive, obviously) and let it run idle for a bit. That charges the capacitors back up, gets rid of any built-up moisture inside the unit, and makes sure all the internal parts are still working. I once had a client store a drive for 18 months and forgot to check it— when they finally turned it on, the capacitors were so dried out they popped. They were lucky we were able to recondition it, but a lot of places won’t do that.
Now, what about prepping the drive for storage in the first place? A lot of people just shove the drive in a box and leave it, but there’s a few steps to prep it too. First, wipe down the exterior with a dry cloth— if there’s any oil, dust, or grease on the outside, that can attract moisture and cause corrosion over time. Don’t use wet cloths or cleaning chemicals, that’ll make it worse. Then, make sure all the terminals are covered. If you have the plastic terminal covers that came with the drive, put them back on. If you don’t, use a piece of electrical tape (not the fancy stuff, just basic vinyl tape) to cover the input and output terminals. That keeps dust and moisture out of the connection points.
Also, label everything. Write the date you stored it, the model number, and the voltage on the box. I can’t tell you how many times we’ve dug through a storage area and found 10 unlabeled VFDs with no idea when they were stored or what model they are. That’s a headache for everyone— you don’t want to have to test 5 drives just to find the one you need.
Wait, let’s talk about common mistakes I see all the time, the ones that make my skin crawl. First, storing drives in a basement or attic. Basements are super humid, especially if there’s a leak, and attics get way too hot in the summer and freezing in the winter. I had a client store 8 VFDs in their attic during a renovation— by the time they realized the attic was at 48°C (118°F) in July, every drive’s plastic casing was warped and the circuit boards were starting to delaminate. Total loss. Second, leaving the plastic shipping wrap on too long. Wait, what? Yeah, if you leave the sealed plastic wrap on for more than a month or two, it can trap moisture inside the wrap, even if the drive is in a dry space. Take the wrap off as soon as you get the drive, but keep the box and foam. Third, storing drives with other chemicals or corrosive materials. If you have a storage area with cleaning supplies, paints, or acids, the fumes can get inside the VFD and eat away at the internal parts. Keep drives separate from those, at least 10 feet away.
Another big one: ESD (electrostatic discharge) protection. I mentioned this earlier, but it’s worth repeating. Even if you’re just moving a drive into storage, don’t touch the circuit board or the internal parts with your bare hands. The oil and dirt on your fingers can damage components, and static from your body can fry tiny parts. If you have ESD gloves, wear them, but if not, at least touch a metal surface (like a workbench) first to discharge any static before handling the drive. And when you put it in the box, make sure the antistatic foam (that soft black or pink stuff) is under and around it, that’s designed to stop static.
Now, what if you have to store drives long-term, like a year or more? Let’s say you overstocked for a project that got delayed, or you have a backup supply for future expansions. Here’s the extra steps you need to take. First, if your storage space isn’t climate-controlled, you can put the drives in sealed plastic bins with desiccant packs. Desiccants are those little packets you get in shoe boxes or electronics, they absorb moisture. You can buy bulk desiccant packs online, and if you seal the bin tight, it keeps the humidity levels low for months. Just make sure you change the desiccant every 6 months, because they get full of moisture. Second, mark the drives with an expiration date of sorts based on storage conditions. If they’re stored perfectly, low-voltage VFDs can sit for up to 5 years without issues, but if they’re in a bad space, that drops to 2 years. We always tell clients to use the oldest drives first, just like perishable goods, because even perfect storage can’t stop gradual degradation over time.
Let me throw in a real example from our shop to drive this home. Last quarter, we had a client who ordered 20 480V VFDs for a new factory line, but the line got pushed back 8 months. They stored the drives in their loading dock, which is open to the elements (they thought “it’s covered, right?”). When they called us to pick them up, 12 of them had corrosion on the input terminals, and 3 had capacitor issues. We had to replace those 15 at a discount, but it cost them more in downtime when they finally got the line up and running because we had to rush the replacements. If they’d just moved them to a spare office closet that was temperature-controlled, they would have been fine. It’s not rocket science, it’s just a little common sense.
So, to wrap this up: storing low-voltage VFDs properly doesn’t have to be a big, complicated chore. It’s just about picking a good space, protecting the drive from the elements, checking on it periodically, and not being lazy with the small steps. If you skip these, you’re risking expensive replacements, delays on your projects, and a whole lot of stress.
Now, if you’ve got VFDs that need to be shipped, or you’re looking for reliable low-voltage VFDs for your next project, hit us up. We’ve got a huge stock of new, properly stored drives, and our team can help you with anything from sizing to installation tips. No hassle, no hidden fees, just solid support for your projects.
Control Cabinet References:
- Electrical Apparatus Service Association (EASA). Storage Guidelines for Medium and Low-Voltage Rotating Electrical Equipment, 2021.
- Allen-Bradley. Variable Frequency Drive Storage and Handling Best Practices, Rockwell Automation, 2022.
- International Electrotechnical Commission (IEC). IEC 60034-1: Rotating Electrical Machines – Part 1: Rating and Performance, 2010.
- NEMA Standards Publication ICS 2-2019: General Requirements for AC Variable Frequency Drives.
- capacitorindustry.com. The Impact of Storage Conditions on Capacitor Lifetime, 2023.
Nanjing Aubo Electric Co., Ltd.
Nanjing Aubo Electric Co., Ltd. is one of the most reliable low voltage vfd manufacturers and suppliers in China. Welcome to wholesale high quality low voltage vfd made in China here from our factory. For more cheap products, contact us now.
Address: No.15, Zhufeng Road , Zhuzhen Town Luhe District, Nanjing, Jiangsu
E-mail: aubochina@aubochina.com
WebSite: https://www.vfd-softstarter.com/
