JWM Screw Jack Ratio Selection – Fast vs Slow Speed
JWM Screw Jack Ratio Selection – Fast vs Slow Speed
JWM screw jacks come in two speed ratios. Choosing the right one is a trade-off between speed and torque.
The Two Ratios
| Ratio | Code | Speed | Torque | Best For |
|---|---|---|---|---|
| 6:1 | H (Fast) | Higher | Lower | Light loads, high-frequency cycles |
| 24:1 | L (Slow) | Lower | Higher | Heavy loads, safety-critical |
How Speed Is Calculated
Lifting Speed = (Motor RPM ÷ Ratio) × Screw Lead
For JWM050 (screw lead = 8mm) at 1450 RPM:
| Ratio | Calculation | Speed |
|---|---|---|
| 6:1 (Fast) | 1450 ÷ 6 × 8 | 1,933 mm/min |
| 24:1 (Slow) | 1450 ÷ 24 × 8 | 483 mm/min |
Which One Should You Choose?
| Your Priority | Choose |
|---|---|
| Speed first | Fast ratio (H) |
| Torque & safety first | Slow ratio (L) |
| Manual handwheel operation | Slow ratio (easier to turn) |
Important Note
The slow ratio provides stronger self-locking – the load stays in position when power is off. For heavy loads or safety-critical applications, always choose the slow ratio.