The Yamato LR-500B is a digital overhead (top-driven) laboratory stirrer tuned for medium-viscosity mixing at higher speed — the faster member of the LR-500 pair. Its gearless direct-drive turns a ø10 mm shaft at 100–1000 rpm with a peak torque of 0.98 N·m (10 kgf·cm), backed by a 100 W brushless DC motor. Speed-feedback control holds the set rate as viscosity changes mid-stir. Ships as the main body including a stainless shaft and 75 mm propeller; the LR-500BA adds the stand and rod as a complete set.
Key Specifications
| SKU | LR-500B |
| Type | Overhead (top-drive) digital laboratory stirrer — main body |
| Speed range | 100–1000 rpm (no load) |
| Max torque | 0.98 N·m (10 kgf·cm) |
| Motor | Brushless DC, 100 W |
| Drive | Gearless direct-drive |
| Shaft diameter | ø10 mm |
| Speed control | Speed feedback control (holds set rate under changing load) |
| Display | Digital 3-digit speed / green-LED torque, 2 steps + overload display |
| Safety | Stops automatically when overloaded |
| Power source | AC 100–125V, 3.5A, 50/60 Hz |
| Included | Stirring shaft (ø10 x 500 mm), 75 mm 4-blade propeller, clamp |
| Speed twin | LR-500A (34–340 rpm, 1.96 N·m) |
| Complete set SKU | LR-500BA (adds stand + rod) |
| List price | $2,695.00 |
Application Profile
- Medium-viscosity mixing at speed — solutions and suspensions that need faster blending than the high-torque LR-500A provides.
- Overhead stirring of large / open vessels — top-driven stirring for volumes and geometries a magnetic stir bar cannot serve.
- Homogenization, dispersion and blending — higher-rpm shear for emulsions, dispersions and dissolutions.
- Continuous / long-run stirring — maintenance-free brushless motor with feedback control for extended runs.
Overhead vs magnetic — when to pick the LR-500B: choose an overhead stirrer when the sample is too viscous or the vessel too large for a magnetic stir bar. Within the LR-500 pair, the LR-500B is the higher-speed / lower-torque option for medium-viscosity work; step to the LR-500A when the sample is thick enough to demand its 1.96 N·m at low speed.
Design Architecture
The LR-500B uses a gearless direct-drive layout: the ø10 mm shaft is driven directly by a 100 W brushless DC motor, eliminating gear noise and wear. The brochure calls out the brushless motor's safety advantage — no brushes, no sparks, no brush replacement — well suited to solvent-exposed benches.
Speed feedback control monitors load and maintains the set rate despite viscosity changes during a stir. Load is shown on a green-LED, two-step + overload torque display alongside a 3-digit digital tachometer; when load exceeds the maximum, an overload lamp turns on and the motor stops automatically. At 3.5A the LR-500B draws slightly more than the LR-500A, consistent with its higher-power motor.
Frequently Asked Questions
What speed and torque does the LR-500B provide? 100–1000 rpm (no load) with a peak torque of 0.98 N·m (10 kgf·cm), driven by a 100 W brushless DC motor through a ø10 mm shaft.
How does the LR-500B differ from the LR-500A? They are a speed/torque pair. The LR-500B is the higher-speed, lower-torque option (100–1000 rpm, 0.98 N·m) for medium-viscosity work; the LR-500A runs 34–340 rpm at 1.96 N·m for thicker samples.
Do I need anything else to use the LR-500B? Yes. The LR-500B is the main body and requires a stand and rod to mount it. Order the LR-500BA set to include the stand and rod, or add a stand/rod set (e.g. LR-41-124) separately.
When should I choose an overhead stirrer over a magnetic one? When the sample is too viscous or the vessel too large for a magnetic stir bar — the top-driven LR-500B serves volumes and geometries a stir bar cannot.
What ships in the box? The LR-500B main body, a stirring shaft (ø10 x 500 mm), a 75 mm 4-blade propeller, and a clamp; speed-feedback control holds the set rate as viscosity changes.
Ordering & Configuration
In the box: LR-500B main body, stirring shaft (ø10 x 500 mm), 75 mm 4-blade propeller, and clamp. A stand and rod are required to mount the unit and are operational accessories — order the LR-500BA set to include them, or add a stand/rod set (e.g. LR-41-124) separately.
Optional accessories: propellers in various types/sizes, vacuum adapter, extra-long stirring shaft (ø10 x 800 mm), glass stirring shaft.
At $2,695.00 the LR-500B is quoted rather than added directly to cart. Confirm at quote:
- Main body vs complete set — LR-500B (this SKU, needs a stand) vs LR-500BA (with stand + rod).
- Speed/viscosity fit — 100–1000 rpm / 0.98 N·m (this SKU) vs LR-500A's 34–340 rpm / 1.96 N·m.
- Shaft and propeller — the 500 mm shaft and 75 mm propeller against vessel depth; long shaft / alternate propellers as needed.
Warranty: per Yamato standard terms — confirm at quote.
LR-500 family: LR-500B (100–1000 rpm, this product) · LR-500A (34–340 rpm, high torque) · LR-500AA / LR-500BA (complete sets with stand + rod).
