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"SKA Series" Rotary Limit Switches
Rotary limit switch for use on machine and ball screw actuators.
SKA Series / RLS-4139







SKA Series Rotary Limit Switch
Features
- Available in two control voltage ratings : 250 or 480, and in three gear ratios.
- Can be used in applications where there is a need to control equipment that rotates and/or reverses.
- Sturdy and compact. Constructed of corrosion-resistant materials, with housing of black anodized aluminium.
- Meets NEMA-4 water tightness requirements.
- Simple to adjust, two stitches one for up/stop and one for down/stop, are activated by the adjustable limit switch nuts which travel laterally when the internal screw is rotated through gear reduction.
- Operating temperature range -20° to + 150°F.
- Lifetime lubricated.
- Can be mounted on right or left extension of actuator worm shaft in any of four quadrants.
- Optional 4-position limit switch available.
Rotary Limit Switch Performance Specifications
Model No. | Max Voltage | Max. Amps | Gear Ratios | Max. Worm Rev. | Max. Rise | Max. Allowable Drift | Notch Adjustment | ||
AC | DC | AC | DC | ||||||
SKA6000AT10 | 250 | 125 | 15 | .50 | 10:1 | 1095 | 1095/TPI | 24/TPI | 1/TPI |
SKA6000AT20 | 20:1 | 2190 | 2190/TPI | 48/TPI | 2/TPI | ||||
SKA6000AT40 | 40:1 | 4380 | 4380/TPI | 96/TPI | 4/TPI | ||||
SKA6000BT10 | 480 | 250 | 15 | .50 | 10:1 | 750 | 750/TPI | 29/TPI | 1/TPI |
SKA6000BT20 | 20:1 | 1500 | 1500/TPI | 57/TPI | 2/TPI | ||||
SKA6000BT40 | 40:1 | 3000 | 3000/TPI | 115/TPI | 4/TPI |

Limit Switch Field Installation Dimensions

Worm Shaft Dimensions
Capacity | "B" Mounting Dimensions | Worm Shaft Diameter |
2 & 3 Ton MS | 6 3/4 | .500 |
3 Ton MS | 6 3/4 | .625 |
5 Ton MS & BS | 7 3/4 | .750 |
10-15 Ton MS & BS | 8 3/4 | 1.000 |
20 Ton MS & BS | 8 3/4 | 1.000 |
25 Ton MS & BS, 35 Ton MS | 10 1/4 | 1.375 |
50 Ton MS & BS | 14 1/4 | 1.500 |
75 Ton MS | 15 1/4 | 1.750 |
100 Ton MS | 14 3/4 | 1.750 |
150 Ton MS | 14 3/4 | 1.875 |

Rotary Limit Switch Electrical Wiring Diagram and Setting Instructions
-
CAUTION: Disconnect power before making any adjustment.
-
Check drift before adjusting limits.
-
Remove screw "A" and nut guide keeper "B" to adjust limits.
-
Run actuator unit to desired limit.
-
Rotate appropriate nut until switch clicks, then turn 1/2 turn more.
-
Replace "A" and "B".
-
Run actuator unit to other limit.
-
Repeat steps 2, 4 and 5 to adjust this nut.
-
Slight adjustments may be necessary.
- Description
- Performance Specifications
- Installation Dimensions
- Electrical Wiring Setting Instructions
- Downloads
- Pricing
SKA Series Rotary Limit Switch
Features
- Available in two control voltage ratings : 250 or 480, and in three gear ratios.
- Can be used in applications where there is a need to control equipment that rotates and/or reverses.
- Sturdy and compact. Constructed of corrosion-resistant materials, with housing of black anodized aluminium.
- Meets NEMA-4 water tightness requirements.
- Simple to adjust, two stitches one for up/stop and one for down/stop, are activated by the adjustable limit switch nuts which travel laterally when the internal screw is rotated through gear reduction.
- Operating temperature range -20° to + 150°F.
- Lifetime lubricated.
- Can be mounted on right or left extension of actuator worm shaft in any of four quadrants.
- Optional 4-position limit switch available.
Rotary Limit Switch Performance Specifications
Model No. | Max Voltage | Max. Amps | Gear Ratios | Max. Worm Rev. | Max. Rise | Max. Allowable Drift | Notch Adjustment | ||
AC | DC | AC | DC | ||||||
SKA6000AT10 | 250 | 125 | 15 | .50 | 10:1 | 1095 | 1095/TPI | 24/TPI | 1/TPI |
SKA6000AT20 | 20:1 | 2190 | 2190/TPI | 48/TPI | 2/TPI | ||||
SKA6000AT40 | 40:1 | 4380 | 4380/TPI | 96/TPI | 4/TPI | ||||
SKA6000BT10 | 480 | 250 | 15 | .50 | 10:1 | 750 | 750/TPI | 29/TPI | 1/TPI |
SKA6000BT20 | 20:1 | 1500 | 1500/TPI | 57/TPI | 2/TPI | ||||
SKA6000BT40 | 40:1 | 3000 | 3000/TPI | 115/TPI | 4/TPI |

Limit Switch Field Installation Dimensions

Worm Shaft Dimensions
Capacity | "B" Mounting Dimensions | Worm Shaft Diameter |
2 & 3 Ton MS | 6 3/4 | .500 |
3 Ton MS | 6 3/4 | .625 |
5 Ton MS & BS | 7 3/4 | .750 |
10-15 Ton MS & BS | 8 3/4 | 1.000 |
20 Ton MS & BS | 8 3/4 | 1.000 |
25 Ton MS & BS, 35 Ton MS | 10 1/4 | 1.375 |
50 Ton MS & BS | 14 1/4 | 1.500 |
75 Ton MS | 15 1/4 | 1.750 |
100 Ton MS | 14 3/4 | 1.750 |
150 Ton MS | 14 3/4 | 1.875 |

Rotary Limit Switch Electrical Wiring Diagram and Setting Instructions
-
CAUTION: Disconnect power before making any adjustment.
-
Check drift before adjusting limits.
-
Remove screw "A" and nut guide keeper "B" to adjust limits.
-
Run actuator unit to desired limit.
-
Rotate appropriate nut until switch clicks, then turn 1/2 turn more.
-
Replace "A" and "B".
-
Run actuator unit to other limit.
-
Repeat steps 2, 4 and 5 to adjust this nut.
-
Slight adjustments may be necessary.
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