Motor amps.2

7 things motor amps tell you about the state of your conveyor chains

Written by Alan Longshaw on 08 July 2020

The amount of work the motor has to do to drive the chain conveyor, as indicated by the power it consumes, provides extremely valuable insight into the operation of the system – allowing you to take actions that save both time and money.

Measuring and monitoring the motor amps should be part of every conveyor operator’s maintenance routine. It’s really easy and inexpensive to do – using readings from the PLC (programmable logic controller) or an amp clamp (clamp meter) – and can indicate so much about the performance and health of the conveyor over time. Here are just seven questions this vital data can help you answer.

1. Is the conveyor overloaded?

Subjecting your conveyor to high or shock loads will place unnecessary stress on the system, leading to increased wear on the chain and sprockets and a shorter service life. If this continues over time, the chain stretch could even lead to chain failure and costly unscheduled downtime.

By measuring the motor amps when the conveyor is running empty and then again at maximum load, you should establish a normal operating range. If the amps drawn suddenly exceed your normal upper limit, this means the conveyor is having to work extra hard and you may have an overloading problem on your hands.

2. Is the conveyor chain properly lubricated?

Good lubrication of the conveyor chain lowers the friction coefficient between the chain components, decreasing wear and increasing service life. It also means the motor has less work to do to keep the conveyor moving, decreasing energy consumption.

When the motor amps increase because the motor is having to work harder, you will know it’s time to relubricate the chain. Some conveyor systems controlled by a PLC may even use the amps being drawn to automatically set off a lubrication cycle. Monitoring motor amps will allow you to optimise the time between lubrication and even experiment with different types of lubrication to maximise the efficiency and lifetime of your conveyor at the lowest cost.

 

3. Is the right conveyor chain tension applied?

Correct chain tension is essential for the conveyor to run smoothly with minimal energy consumption and wear. When a chain is correctly tensioned, you will notice only a very small fluctuation in motor amps as the chain is pulled through the conveyor. If it is under or over-tensioned, however, more energy will be required for the chain to pass through the conveyor and the motor amps will increase.

 

4. Are the conveyor chain track and sprockets correctly aligned?

Misalignment with the track or sprockets will increase friction and, therefore, wear. To overcome this extra friction, the conveyor driver motor has to work harder, drawing more energy. As soon as the alignment issue is fixed, the motor amps will drop back down to a normal operating level.

5. Is the conveyor chain coming to the end of its service life?

When a new chain is fitted, it undergoes a process of bedding in, which involves the chain components passing over each other until the surfaces become smooth. The amount of time required for the chain to bed in depends on the surface finish, the quality of component manufacture and lubrication, but is often around three months. During this time, the motor amps will steadily increase.

In the next phase of the chain’s life, it will wear over time. This wear can be graphed by monitoring the motor amps and confirmed by measuring the chain stretch. At the point where the chain’s hardened surfaces wear away, the chain will undergo accelerated wear as the unhardened surfaces pass over each other. This will lead to a significant increase in motor amps and is a sign that the chain is coming to the end of its life.

6. Is there any internal damage to the conveyor?

Any part of the chain structure that is damaged and impedes the smooth running of the chain system will require the motor to work harder to overcome this struggle. A sudden increase in motor amps could, therefore, be a sign that bearings have failed, flights have become detached or foreign objects have become lodged in the system – and will need inspection to resolve the issue.


7. How much money have I saved by switching from steel to wooden flights?

If you have switched from steel scrapers to wooden ones, you should see an instant decrease in motor amps. INNO flights, made from multi-laminated beech wood, save up to 60% of the weight of traditional steel scrapers, without compromising on strength. The conveyor runs more efficiently because more of the energy drawn by the motor goes towards moving product than its own components – and electricity consumption decreases overall. Over time, this can add up to huge savings in energy costs. Because the flights are lighter, they also decrease the pressure exerted on other conveyor components, leading to less wear, longer service life and lower replacement costs.


Get in touch to discuss how we can cut your conveyor running costs.


Safety note: Before carrying out any electrical work on your conveyor, ensure you have completed the appropriate risk assessments and method statements. Electricity is unforgiving and its sentence deadly, instantaneous and without an appeal.

Topics: Conveyor chain, condition monitoring, motor amps

Alan Longshaw

Written by Alan Longshaw

Technical Sales Engineer Alan Longshaw has more than 25 years of experience in the conveyor chain industry. He began his career designing and drawing chains for a UK manufacturing company before moving to a sales role after realising he could improve the flow of information between technical and sales teams. His strong mechanical and consultative background enables him to tackle the most complex conveyor challenges, devising solutions that save customers both time and money.

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