LRA vibration motors lead on speed, noise & power consumption

by Vianie Li & Cecile de Veyra

The need for haptic technology in devices such as smartphones and wearables is sustaining efforts to produce vibration motors that offer higher stability and reliability. One trend is in favor of linear resonant actuator (LRA) motors, which have a precise vibration profile, fast speed measured in response time, and low noise and power consumption. They are already used in high-end handsets from brands, including Samsung, Huawei, Xiaomi and Meizu, that have migrated from eccentric rotating mass (ERM) motors. Apple introduced LRA motors to some devices in 2011 and has been using a custom version branded the Taptic Engine since the iPhone 6s.

In China, LRA units are available with a maximum mechanical noise of 35dB and a life span of more than 1 million cycles.

Chinese manufacturers of vibration motors mostly offer mini DC types, with mainstream products having 5,000 to 30,000rpm speed, 1.5 to 12V rated voltage, 25 to 300mA no-load current and 0.01 to 0.5W rated power. In addition to mobile phones and wearable devices, these units are used in medical devices and toys.

There are three-phase asynchronous vibration motors as well. In vertical- and horizontal-mount designs, they are mainly for the hydropower, metallurgy, chemical and construction markets. Explosion-resistant units are also available.

Raw materials and components such as bearings, shafts, magnets, coils, adhesives and cases come from domestic or foreign sources, depending on buyer requirements. Input costs rose slightly in 2020 and early this year, increasing product prices by 10 percent. Costs and quotes are expected to stabilize in the months ahead.

ERM, 200,000rpm±20% no-load speed

Rated at 127V, 60Hz and with a class F insulation, this 7025 ERM vibration motor from Dongguan City Lianfeng Motor Co. Ltd has a clockwise rotation. At no load, its speed is 200,000rpm±20 percent and power 150W±20percent. The rated power is 350W.

The minimum order quantity is 1,000 units. Lead time is 15 days.

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ERM, 3,400rpm no-load speed

The 5420 from Dongguan City Lianfeng Motor Co. Ltd is an ERM vibration motor with a counterclockwise rotation and less than 80dB noise. Its no-load speed, current and power ratings are 3,400rpm, 0.48A and 105W. The unit meets CB, CCC, CE, RoHS and UL requirements.

An order of at least 2,000 units is required. This has a 15-day lead time.

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LRA, Z axis

From Leader Micro Electronics (Huizhou) Co. Ltd, this Z-axis LRA vibration motor, the LD0825AA, has 1.8VAC rms and maximum 90mA rms rated voltage and current. Its input frequency range is 225 to 255Hz, minimum insulation resistance 10Mohm at 100V and tolerance 240ohm±10 percent. At maximum, the rise and fall times are 50ms and 80ms.

The supplier requires an order of 100 units. Delivery is within seven days.

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ERM, 9,000rpm minimum rated speed

This LCM0820A2860F coin-type ERM vibration motor from Leader Micro Electronics (Huizhou) Co. Ltd supports clockwise and counterclockwise rotations. It has 9,000rpm minimum rated speed and 10Mohm minimum insulation resistance. The operating and rated voltages are 2.7 to 3.3VDC and 3VDC, and the maximum rated current is 80mA. Operating temperature is -20 to 60 C.

The 100-unit minimum order requirement has a lead time of seven days.

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ERM, 16,000rpm no-load speed

Suitable for model trains, this 12V-rated ERM vibration motor from Suntech Development Co. Ltd, the SF1215, has 16,000rpm and 0.18A no-load speed and current.

Order quantity is negotiable. Delivery takes 30 days.

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3kg.cm torque with load

Suntech Development Co. Ltd markets this SR385G vibration motor with 70rpm speed with no load and 61rpm with load, and 3kg.cm torque with load. Its rated voltage is 12V and the no-load current 0.18A.

The negotiable minimum order is for delivery within 30 days.

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