HOIST CLINIC WITH ACE INSPECTION MANAGER JERAMY NICHOLS
The last thing you want to hear when working with the equipment you depend on in your production is any sound that might indicate a mechanical issue. If you suspect the hoist on your overhead crane has a problem, one troubleshooting technique is to try to run it when other heavy equipment is not in use so you can hear more clearly for telltale sounds that might help diagnose a problem. Then, if your hoist makes one of these noises, you'll know it's time for service.
Chattering Sounds Coming from Your Hoist
During certain conditions, a hoist might make what could be identified as a chattering noise. This sound would not be as loud as the one a squirrel makes when communicating a warning to your inquisitive dog, but something along those lines. It can be distinctive enough to notice and will depend on the noise level of the workplace it operates within whether you can hear it. If the ambient noise in your working environment, such as what you might find in a metal processing plant, drowns out any warning sounds, you may not be able to listen for a problem until you're standing right beside your hoist. If discovered too late, the damage to it could already be done. The horsepower size of the motor can also determine how loud the sound will be; the bigger the motor, the louder it will be.
Your hoist's motor, or its brake assembly and coil, makes the chattering noise. One thing your hoist might be experiencing is voltage drop. The longer the cord that gives power to the hoist, or the longer the length the hoist's electricity needs to travel, the less voltage you'll have coming out at the end and the least amount of amps you'll have to work with.
Let's say you have a hoist right next to an outlet. If you were using a small gauge wire 100-foot extension cord with a single phase 110/120-volt hoist, and it's making a chattering sound, you might want to drop down to a shorter length cord. As far as length, if you use a lower gauge but thicker diameter wire, you'll have the voltage and amps needed to correctly power your hoist and prevent the voltage drop that can create hoist chattering.
If you were to run an extension cord for a household drill, a saw, or something with a smaller motor, a general extension cord would be fine. But a heavy-duty cord or wiring is needed for industrial motors because they will pull more amperage.
On a larger crane, say a three-phase system, your wiring will be a little bit different, but it's the same idea—you've got to allow the needed amps and voltage to run to the machine. Higher voltage is required for more horsepower and torque for heavy duty motors.
Here at Ace, when we're installing wire on a crane for a customer, we want to ensure that we're not overselling them on something too big for what they need or underselling them on something that's going to cause problems for them down the road.
It seems counterintuitive when calculating wire size, the smaller the gauge number, the bigger the wire. Larger diameter wire will allow the amps to draw through. Did you ever put your finger over the end of a small water hose and watch it spray out water? Well, the bigger the hose, the more spray you'll get out of it even though the pressure will always be the same coming through the hose. It's the same idea with electrical wiring. See Ace's Wire Sizing Guide.
Popping Sounds Coming From Your Hoist
A popping sound coming from a hoist could indicate a couple of different issues. It might sound like knuckles cracking but not as loud as a balloon or popcorn popping. Something more like when your tire goes over a curb. When a chain link has stretched wear, it is called peanutting or the shape is referred to as figure eight. Technically, per regulation and per manufacturer, there is a certain amount of allowable load chain stretch. You're allowed up to 2.5% stretch for a manual chain hoist, but on powered hoists, you're allowed up to 1.5% stretch. If your hoist load chain is too stretched when it runs over the upper sprocket inside the housing, it will try to climb out or jump out of the sprocket connection and make a popping sound.
The inside saddles of load chain links are weight-bearing surfaces that rub together. If they rub without being adequately lubricated, those surfaces will grind. If any gritty or corrosive substance such as dirt, chemicals, or paper dust from your work environment gets inside the load chain saddles, it could lead to grinding. Grinding wears down the interlinking chain, misshaping and stretching the link from its original size and shape, so when it goes over a sprocket, the connection attempts to jump out of the sprocket and makes a popping sound.
Load chain saddle wear.
One way to ensure you don’t miss isolated points of interlink wear is to hand check every single chain link. As a result, wear might only appear in particular sections. For example, a facility could use a hoist to lift a below-the-hook device that lifts materials. In this case, the hoist might only lift 6 to 9 feet at a time during its workday, so the load chain wear pattern might only show up in the parts of the chain that get used during the more minor lift.
In a metal facility, it is possible for air-contaminated corrosive materials, extreme temperature fluctuations, hot and cold stresses, or humidity can wear and/or elongate load chain links. Again, wear tolerance must conform to regulation safety standards but is also established by each hoist manufacturer. Any chain link distortion inhibiting the performance of your hoist must be replaced.
When the load chain is replaced, thoroughly inspect the sprocket and the guides inside the hoist for wear or damage, as they may also need to be replaced. (See ASME B30.16 – 2022)
Hoist sprocket wear.
How Do You Know When to Replace a Hoist Load Chain?
Check for interlink damage, especially shoulder wear on each link of your load chain. This should indicate sprocket wear. Check if your load chain is stretched, misshapen, scratched, or worn, or if you find weld spatter, weld marks, or grinding marks. If your chain has any of these defects or is past the wear tolerance, then the chain would need to be replaced.
Load chain weld spatter.
Load chain shoulder wear.
How Do You Prevent Damage to a Hoist Load Chain?
Making sure your chain has proper lubrication is the best way to ensure a longer working life for your load chain. Use an EP additive when applying extra pressure on a load chain. If you manufacture food products, use a good food-grade lubricant. If you've got a high dust environment, such as a paper mill, or a metal fabrication shop, lubrication can hinder the chain. The food or dust particles and their wax might stick to it and cause problems.
Here in the southern U.S., we have a lot of agriculture customers. We had a customer running cranes in a peanut butter manufacturing facility. Peanuts and dust would get in their hoists' load chains, and within a month, we were replacing chains almost every month because they were wearing so fast. The solution was to replace the hoists with a better grade of chain and a better choice of hoist.
Chemical or galvanizing plant customers or any customers whose facilities handle caustic materials may find a lot of damage occurring in their hoist load chain. I'd recommend using a chain sling or other types of lifting slings instead of the load hook and chain coming into contact with chemicals. This could prevent corrosion when working in or close to a chemical area, especially if lowering into a dip tank.
When your load chain is compromised, it might start making a warning noise such as chattering or popping. To avoid the costs involved with potential problems, always inspect your hoist's chain link by link before use each day. Look for any peanutting, misshapen figure eights, welding spatter, or grinding wear that might disrupt your production process, and replace them if needed. For an expert opinion, schedule an appointment with any Ace service technician in your area. They can inspect your hoist and chain to determine its condition and make recommendations. If you have any questions, please feel free to call me at (904) 430-3598.
Author Jeramy Nichols
Jeramy has been in management for 27 years from auto part sales, heavy equipment repair, military helicopter production, and compressor production. He attended Troy University for Business Management and Auburn University for Lean Manufacturing/Six sigma. Since 2012, Jeramy has served Ace in various rolls in service with working in the field, inspection review, repair quoting, InspectALL admin, and inspection training. Jeramy is also part of ASME B30.16 and B30.17 subcommittees, and CMAA Safety/Service and Spec #76 committees.
Jeramy lives in Troy, Alabama, with his wife, 3 daughters and 1 son, 1 grandson and 2 more grandchildren on the way, 2 dogs, 5 chickens, and a goat. He enjoys spending time with his family and friends, working on the farm and being outdoors.
Jeramy believes TEAMWORK consists of 3 aspects: Cooperation, Communication, and Support!