In crushing and screening plants, the star of purchasing discussions is always the main crusher motor; it is the largest power, and the highest price is paid for it. Yet the number of motors that actually keep the plant standing is far greater: vibrating screens, belt feeders, dozens of metres of conveyor lines, by-pass belts and dust suppression equipment. When any one of these motors stops, the plant cannot produce, even if the crusher is running. As a manufacturer, we have supplied motors to quarries and crushing-screening plants for years, and we can say it clearly: most unplanned stoppages come not from the main crusher but from these auxiliary motors that are assumed to be "small". We covered the power and speed selection of the main crusher motor in detail in a separate article; you can reach our crusher and stone crushing plant motor selection guide here. The subject of this article is that large army of motors around the crusher: how to select and quickly supply the screen, feeder and belt drives.

The Plant's Motor Inventory: One Crusher, Many Auxiliaries

In a mid-sized crushing-screening plant the typical picture is this: one or two crusher motors, two or three vibrating screens (each twin-driven), one belt feeder, and between five and fifteen conveyor belts. In other words, more than ten auxiliary asynchronous motors turn per crusher in the plant. In the purchasing plan, these motors must be thought of not one by one but as a fleet: common power groups are identified, spares are stocked by these groups, and you work with the supplier from a single list. This approach both strengthens your hand in price negotiations and ensures the right spare is on the shelf at the moment of failure.

All these drives in the field are in the three-phase motor class fed from a 380-400 V grid, and they all share a common denominator: heavy dust, vibration, open air and long shifts. For this reason, every motor brought into the plant should be selected not from the standard products listed in catalogues as "general purpose" but from series configured for these conditions. Below we handle each motor group one by one.

Electric motors driving vibrating screens and conveyor belts in a crushing-screening plant

Vibrating Screen Motors: The Rules of Twin Drive

In vibrating screens, the heart of the screening plant, the common design is twin drive: two motors placed on either side of the screen body drive the eccentric mechanism together and produce the vibration required for screening. This structure gives rise to three important purchasing rules:

  • Both motors must be replaced together. In a twin-drive system, if one motor is worn and the other new, the load sharing is upset, the vibration pattern changes and screening efficiency drops. Even if only one motor fails, renewing the pair together is the correct practice for screen life.
  • The motors must be exactly identical. Same power, same speed, same frame; preferably the same production batch. When you say "twin motors for a vibrating screen" while ordering, we prepare the shipment with matched products.
  • Vibration resistance is essential. Unlike a normal machine motor, the screen motor runs under continuous vibration. A reinforced bearing structure and a rigid cast iron frame are not a preference but a requirement in this application.

In screen drive, the speed is determined by the screen manufacturer according to the screen's design vibration frequency; in replacements, stay faithful to the speed on the existing motor's nameplate. In belt-pulley drives, the pulley diameters are also part of the vibration setting; changing the pulley size when replacing the motor upsets the screen's character.

Belt Feeder Motors: The Master of Starting Under Load

The belt feeder beneath the bunker takes on the plant's most thankless task: it stops with tons of material on it and starts again under that same load. For this reason, the decisive criterion in feeder motor selection is not nominal power but starting torque. A motor with high starting torque that can comfortably start under load, together with an appropriate gearbox, is needed; in most feeders a 1500 rpm motor works with a high-ratio gearbox, and in heavy applications the torque reserve is increased with a 1000 rpm motor.

The second critical matter in the feeder motor is the environment: under the bunker is the dustiest and most impact-prone area of the plant. IP55 protection class and a cast iron motor frame should be accepted as standard in this area. Our stone crushing screening plant motors in the production program are configured precisely for these conditions: IE4 efficiency class, 0.25 kW - 355 kW power range, various speed alternatives led by 1500 rpm, an impact-resistant cast iron frame, IP55 protection and a reinforced bearing structure.

Conveyor Belt Motors: The Veins of the Plant

The belt lines running from the crusher to the screen, and from the screen to the stockpile, make up the largest share of the plant's motor count. The most preferred speed in conveyor drive is 1500 rpm; the belt is driven through a gearbox and the belt speed is adjusted with the gearbox ratio. On long or inclined lines requiring higher torque, 1000 rpm motors come into play. On our conveyor belt electric motors page you can find IE3 and IE4 options in the 0.55 kW - 355 kW range.

The key to the purchasing strategy in belt motors is standardization. Using eight different motor types in a plant with twelve belts means stocking eight different spares. When designing or renewing the lines, gather the powers into as few groups as possible; for example, combine short belts at one power and long belts at a second power. This way, two spare motors insure almost the entire line. We explained the fast-replacement procedure for a belt motor failure step by step in our conveyor motor emergency replacement article.

Belt feeder and conveyor line drive motors at a quarry

The Forgotten Items: Dust Suppression, By-Pass and Auxiliary Equipment Motors

When drawing up the plant motor list, there is one more group that is often skipped: the water pump of the dust suppression system, the under-screen by-pass belts, the stockpile spreaders and the maintenance workshop equipment. These are small-power motors, but their effect is not small when they fail; when the dust suppression pump stops, environmental regulations may require the entire plant to be stopped. When requesting a bulk quote, we recommend you add these items to the list too: small motors take up no room in shipment and have a limited effect on the price, but the cost of being left without a spare is high.

In water pumps 3000 rpm is used, and in fan and exhaust applications 1500 or 1000 rpm motors depending on the application. This whole small group is always ready in our stocks and is added to your main shipment to be sent in a single delivery.

The Information to Gather From the Field When Ordering

To finalize quote requests from a crushing-screening plant as quickly as possible, it is enough to gather the following from the field:

  • A nameplate photo for each motor: Power, speed, frame, mounting type and connection information are captured in a single frame. If the nameplate is erased, note the equipment the motor is connected to and the pulley/gearbox information.
  • Application description: One-sentence descriptions such as "screen twin drive", "under-bunker feeder", "35-metre inclined belt" are often even more valuable than the nameplate for us to recommend the right product.
  • Operating pattern: Daily operating hours and season length shape our IE3/IE4 recommendation and the spare plan.
  • The site's electrical infrastructure: Grid or generator? On generator-powered sites, starting current planning must be done at the quote stage.
  • Delivery conditions: Site address, unloading capability (forklift/crane) and preferred delivery date.

A request that comes with this information turns into a quote, priced item by item, with lead times and transport included, within the same day. Requests that come with incomplete information, on the other hand, lose days through rounds of correspondence; every day lost is production lost in the season.

Mounting Types: The Condition for Fast Replacement in the Field

In a crushing-screening site, motor replacement is mostly done in the open, under difficult conditions; for this reason, choosing the correct mounting type directly affects the replacement time. In belt and feeder drives, foot-mounted (B3) motors are used with a belt-pulley or gearbox connection; in screen drives, foot or flange connections are seen depending on the screen manufacturer's design. In a like-for-like replacement, preserving the existing mounting type is essential: taking a B35 instead of a B3 mostly causes no problem, but taking a B3 instead of a B5 requires chassis fabrication. Sending a photo of the motor's connection arrangement together with the nameplate is enough for us to finalize the mounting type.

Motor Life in a Dusty Environment: What Are You Paying For?

The return on the price you pay when selecting a motor in a crushing-screening plant is gathered under three headings:

  • Protection class (IP55): Stone dust is abrasive and works into every gap. The IP55 frame, fan and terminal box prevent dust from reaching the windings.
  • Frame material: Flying stone, striking buckets, a vibrating chassis... The cast iron frame carries these impacts; thin-framed motors are short-lived on this site.
  • Insulation and thermal resistance: In motors running in the open in summer, the F insulation class provides a winding temperature reserve.

These three items are the very difference from products that look cheap in an electric motor prices comparison but do not last a single season in the field. In plant motors, total cost is not the purchase price; it is the sum of price + downtime + replacement labour.

Efficiency Class: Is IE4 Sensible in a Seasonally Running Plant?

Crushing-screening plants mostly run on long shifts, uninterrupted throughout the season. In belt and screen motors turning 10-16 hours a day, the efficiency difference the IE4 class provides may look small per motor, but in a plant of fifteen to twenty motors it turns into a serious electricity saving by the end of the season. You can examine all power and speed options in our IE4 electric motors category. Only in motors that wait on standby or run an hour or two a day is the IE3 choice defensible on budget grounds; for main-line motors our recommendation is clearly IE4.

When making the efficiency decision, do this simple calculation: multiply the total power of the belt and screen motors in your plant by the daily operating hours and the number of season days. Even a few percent of the resulting kWh figure closes the price difference between IE4 and IE3 in a single season at most plants. What is more, because IE4 motors run at a lower temperature, bearing and winding life in a dusty environment is also extended; that is, the efficiency investment is at the same time a durability investment.

Spare Stock Plan and Supply Agreement

Anyone who runs a plant whose screen motor fails in mid-season knows the hourly loss. The practical plan we recommend is this: at least one spare motor from each power group used in the plant should be on site; for vibrating screens the spare must definitely be stocked as a pair; for belt motors, one spare per common power group is enough. Once you share your spare list with us, we clarify together which items are always ready on our shelf and which should stay with you. With annual supply agreements aimed at the mining and aggregate sector, we reserve critical motors on your behalf; the details are in our mining motor supply contracts article.

The return on managing an industrial electric motor fleet from a single manufacturer is not only price: the nameplate records of all your motors are kept with us, and when you say "the motor on belt number 3" over the phone, which product will be shipped is clear. You can find our other guides specific to the crushing-screening sector in our crusher and stone crushing motors blog category; for our entire product range you can visit our hemmotor.com homepage.

Frequently Asked Questions

One of the motors on my vibrating screen has failed; can I not just replace that one?

Technically the screen will turn with a single new motor too, but we do not recommend it. The performance difference between the old and new motor upsets load sharing in twin drive; the new motor constantly takes more load, the vibration pattern changes, and both screening efficiency and bearing life are adversely affected. The correct practice is to renew the twin-drive motors together with matched products. When you order a pair, we send the two motors matched from the same batch; the sound old motor can also be put to use as a spare on your shelf.

My feeder motor keeps tripping the thermal; should I buy a larger motor?

Not always. Thermal tripping in most cases stems not from the motor being small but from the under-load starting scenario being set up wrongly: starting with the bunker full, an unsuitable gearbox ratio or starting method may be the real source of the problem. First the existing motor's nameplate, gearbox ratio and starting conditions should be assessed together; we do this analysis within minutes over the phone. If a power increase is genuinely needed, we offer a solution with a motor one size up, with high starting torque and from the same frame family.

Is it more economical to buy belt motors all at once in bulk or as they fail?

Bulk purchasing almost always pays off. A list given all at once allows volume-based negotiation; the motors are matched from the same series, the spare plan simplifies, and transport is gathered into a single shipment. Buying as they fail, on the other hand, means an emergency supply premium, separate transport and downtime cost each time. Our recommendation is to identify the ageing motors during pre-season maintenance and price the replacement + spare need with a single list. The winter maintenance period is the right time for this: while the plant is already stopped, motors are removed and assessed, the order is planned to be ready for the season, and at the spring opening all lines come online with renewed motors. We of course respond to mid-season emergency requests too; but the price and the comfort of planned purchasing are always better.

Get a Quote: Every Plant Motor From Screen to Belt on a Single List

Send us the list of screen, feeder and belt motors in your plant; let us come back with twin-drive matchings, a spare plan and transport included in a single quote. In-stock products are shipped the same day; in pre-season renewal plans we order the shipment according to your maintenance calendar. You can reach our sales team at +90 (532) 345 49 86 or send your quote request through our contact us page. With manufacturer assurance and a product suited to the field, let your plant get through the season without stoppages.

For investors building a new plant or increasing capacity, we are with you at the project stage too: let us identify the power groups of the screen, feeder and belt motors over your project together, and set up the standardization correctly from the very start.