Feed Mixer Electric Motors

A feed mixer motor is the three-phase motor, usually 4-pole (1500 rpm), that turns the mixer's agitator shaft slowly through a gearbox or a belt drive. Its power is set by the batch weight loaded into the vessel and by the mixer type: manufacturer catalogues show 3 kW on a 1-tonne farm-type vertical mixer and 45–55 kW on a 4-tonne industrial twin-shaft mixer. The real test for a mixer motor is starting, because the mixer is often restarted with a full vessel.

On this page you will find the motor requirements of vertical screw, horizontal ribbon and twin-shaft paddle mixers, the difference between farm and industrial types, motor-gearbox matching and loaded starting. How grinder and mixer motors differ is set out side by side in this blog post; this page covers only the mixer. For models and current prices see Buy Electric Motors Online.

Feed mixer types: vertical screw, ribbon and paddle

Vertical screw mixer

A vertical screw turns in the centre of a cylindrical or conical vessel. The screw picks up feed at the bottom, carries it up inside a central tube and spills it outwards at the top; the material falls back by gravity and re-enters the screw. Its simple design, small footprint and low cost make it common in on-farm feed units. The motor sits on top of or beside the vessel and drives the screw through a gearbox or belt. On models fitted with a grinder intake at the base, mixing and grinding happen in the same unit but with separate motors.

Horizontal ribbon mixer

Inside a horizontal trough, inner and outer ribbons on the same shaft push the material in opposite directions. A ribbon mixer is gentle on fragile and fibrous material and suits liquid addition. One manufacturer catalogue gives a mixing time of 3–6 minutes per batch. The motor sits at the end of the trough and drives a gearbox on the shaft.

Single- and twin-shaft paddle mixer

In a paddle mixer, angled paddles on the shaft throw the material both radially and axially. In single-shaft types, according to one manufacturer, the shaft typically turns at 30–60 rpm. In twin-shaft types two shafts rotate in opposite directions and a fluidised mixing zone forms in the middle of the trough; this design brings mixing time below one minute or to around two minutes. In a twin-shaft mixer both shafts are driven from one motor through a gearbox; the number of motors depends on the machine maker's design.

Farm-type vertical mixer versus industrial horizontal mixer

A vertical mixer has low power but runs for a long time; a horizontal mixer has high power but runs briefly. In motor selection this turns into two separate questions: on a vertical mixer the motor must turn under load for long periods without overheating, while on a horizontal mixer it must manage a heavy start again for every batch.

Example: energy used per tonne

Let us compare two machines from the catalogues. The motor is assumed to run at full nameplate power on both machines; this is an upper-limit calculation.

• Vertical mixer, 1000 kg batch, 3 kW motor, 12 minutes mixing: 3 × 12 / 60 = 0.6 kWh, i.e. about 0.6 kWh per tonne.
• Twin-shaft horizontal mixer, 1000 kg batch, 22 kW motor, 2 minutes mixing: 22 × 2 / 60 ≈ 0.73 kWh/t.
• If 1 tonne of feed per hour is needed, either machine will do; if 10 tonnes per hour are needed, the vertical mixer cannot keep up, because a single batch takes 12 minutes.

Conclusion: energy per tonne is similar, but hourly capacity is completely different. Mixer selection is therefore made on capacity first, and motor power follows from that choice. The exact value is in the mixer maker's data sheet.

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How many kW for a feed mixer motor? Catalogue values

A) Motor powers seen on mixers on the market

This machine group shows motor options of roughly 2.2–55 kW depending on manufacturer model and capacity. The smallest value belongs to small ribbon mixers at pilot scale and the largest to 4-tonne twin-shaft mixers. At the same batch weight, power changes with type: one manufacturer gives 37 kW for a single-shaft paddle mixer and 30 kW for a twin-shaft mixer at 2000 kg per batch. Values in the table are the main motor of a single mixer; the pneumatic or electric drive of the discharge door and the liquid dosing pump are counted separately.

The main factors that raise power are batch weight, the bulk density of the product, liquid content and the peripheral speed of the agitator. As molasses or fat content rises, the mix becomes heavier and stickier; that is why makers may offer two motor powers for the same vessel.

B) Matching motors in the DRG range

DRG Motor is a manufacturer, supplier and seller of electric motors. Our 4-pole motors suitable for mixers cover 0.25–355 kW, with aluminium frames up to 11 kW and cast iron frames at higher powers. The whole 2.2–55 kW catalogue range is covered by the DRG range. The gearbox is not a DRG product; the motor is chosen with the flange and shaft that fit the mixer maker's gearbox.

Motor and gearbox: speed, torque and mounting

Gearbox ratio and output torque

If the paddle shaft turns at 30–60 rpm, the gearbox ratio with a 1470 rpm 4-pole motor is roughly between 24.5 and 49. Example: if the 22 kW DRG-180L-4 drives a gearbox with a 40 rpm output, the ratio is about 36.75 and the shaft torque, ignoring losses, is 9550 × 22 / 40 ≈ 5250 Nm. Gearbox losses reduce this value slightly. The gearbox must be selected for this torque and for the peak torque at start; a larger motor does not protect an undersized gearbox. Our gearbox output calculator does this arithmetic for you.

Mounting and belt drive

On industrial horizontal mixers the motor is often flange-mounted (B5) directly to the gearbox, or foot-mounted (B3) on a base and joined by a coupling. On vertical mixers the motor sits on the platform at the top of the vessel and may drive the screw by belt; one manufacturer offers vertical mixers with either a direct-coupled geared motor or a V-belt drive. In a belt layout, belt slip softens the sudden load at start somewhat, but if tension is weak the belt slips when starting with a full vessel. Take the final mounting arrangement and shaft dimensions from the mixer supplier's drawing.

Starting with a full vessel

A mixer is normally started empty and material is dropped onto the turning agitator. After a power cut, an overload trip or an emergency stop, however, the mixer stays full and has to be restarted. At that moment the motor has to set a settled, packed mass in motion.

Starting method

The DRG-180L-4 has a rated torque of 142.9 Nm and a starting torque ratio of 2.0, so it can deliver about 286 Nm at start on direct-on-line. With star-delta starting this drops to a third, about 95 Nm, which is only two thirds of rated torque. A full mixer often will not turn with this torque; the motor stalls in the star stage and the overload trips. That is why soft starters or inverters are preferred on industrial mixers; an inverter gives high torque at low speed and breaks up the mass gently. The star-delta starting guide sets the options side by side. Panel and starter settings should be made by a qualified electrician.

Molasses, fat and discharge

In batches with liquid addition, the load rises within a few seconds after the liquid is sprayed. Watching motor current at that moment shows both an excessive liquid ratio and paddle wear. Keeping the agitator running while the discharge door is open empties the trough quickly and makes the next start easier.

DRG motors and price list for feed mixers

The models in the table are chosen from the power steps seen on vertical and horizontal mixers; values are store data:

Models up to 11 kW also have an aluminium frame option; on dusty, vibrating mixer platforms a cast iron frame is chosen more often. For anyone looking for an industrial feed mixer motor, the 18.5–45 kW cast iron models match the power range of industrial horizontal mixers.

Feed mixer motor price

DRG MOTOR motors are guaranteed against material and manufacturing defects for 2 years from the delivery date (warranty certificate).

Motors in this power range

• DRG-100L2-4 – 3 kW – 1450 rpm – 100L cast iron
• DRG-132S-4 – 5.5 kW – 1460 rpm – 132S cast iron
• DRG-160L-4 – 15 kW – 1465 rpm – 160L cast iron
• DRG-180L-4 – 22 kW – 1470 rpm – 180L cast iron
• DRG-200L-4 – 30 kW – 1475 rpm – 200L cast iron
• DRG-225S-4 – 37 kW – 1485 rpm – 225S cast iron

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Feed mixer motor: common questions

How many kW for a 1-tonne feed mixer?

Catalogues show 3 kW on a 1-tonne vertical mixer and 18.5–22 kW on a 1-tonne twin-shaft horizontal mixer. The difference comes from mixing time and type. The exact value is on the machine nameplate.

What speed should a feed mixer motor be?

Usually a 4-pole motor of about 1450–1485 rpm is used, and shaft speed is reduced by gearbox or belt. Do not change the input speed of the existing gearbox.

Why won't the mixer start when full?

With star-delta starting, starting torque drops to a third and may not be enough for a full vessel. A loose belt, a broken paddle or a gearbox fault can also be the cause. Do a mechanical check first, then review the starting method.

Where can I see the feed mixer motor price list?

The live table on this page pulls current prices from the store. Every other rating is browsable in the online store.

Contact us with the mixer nameplate, batch weight and gearbox label and we will choose the right motor together. Phone +90 (542) 666 11 11, e-mail [email protected], contact page. For all models see Buy Electric Motors Online.