Description
Schischek ExMax-50.75: compact, safe, and universal Ex actuator
ExMax-50.75 is the explosion-proof actuator for critical HVAC applications in the chemical, pharmaceutical, and industrial sectors. It can be directly coupled to a 16×16 mm shaft, has IP67 protection, and features a universal power supply of 24…240 VAC/DC. As a result, it fits almost anywhere. In addition, you can select one of five running times on site (40/60/90/120/150 s), while the 95° stroke with 5° preload ensures reliable closing.
All in all, this delivers a robust, cost-efficient solution for air dampers, ball valves, and butterfly valves in ATEX zones 1, 2, 21, and 22.
Key features
- Explosion-proof (ATEX/IECEx) for gas and dust: zones 1, 2, 21, 22; protection up to T6/T5. Therefore suitable for demanding environments.
- 50/75 N·m torque (field-adjustable) with 100% overload protection. At the same time, the housing remains compact and lightweight (~9.5 kg).
- Universal power supply 24…240 VAC/DC, on-off and 3-point control; selectable running times 40–150 s/90°.
- IP67 aluminum housing; options CTM (seawater-resistant coating) or VAM (stainless steel). This keeps the actuator reliable offshore and in aggressive environments.
- Integrated heating down to −40 °C and a safety temperature Sensor. As a result, operation remains stable even in severe cold.
- Simple commissioning with auto-setup, manual override, and clear angle indicator. In addition, auxiliary switches (-S) are available.
Technical specifications
| Type | ExMax-50.75 (size M) |
| Torque | 50 or 75 Nm, selectable |
| Supply | 24…240 VAC/DC ±10%, 50/60 Hz |
| Control | On-off and 3-point (selectable, SB 1.0 wiring diagram) |
| Running time | 40 / 60 / 90 / 120 / 150 s per 90° (field-adjustable) |
| Stroke | 95° incl. ~5° preload |
| Shaft connection | Double square 16×16 mm, direct coupling |
| Protection | IP67; ATEX 2014/34/EU; IECEx; CE 0158 |
| Temperature | −40…+40 °C (T6) or −40…+50 °C (T5) |
| Housing | Aluminum; option CTM (marine coating) or VAM (stainless steel) |
| Weight | ~9.5 kg (Al), ~15 kg (stainless steel) |
| Accessories | ExBox (Ex-e terminal box), ExSwitch (external auxiliary switches), HV-MK manual override, AR-16 reduction bushing, Kit-S8 cable glands |
Available actuators in the ExMax-M series | 30-150 N·m
ExMax-M | with spring return | 30…60 N·m | Zone 1, 2, 21, 22
| Type | Torque | Spring return | Control | Datasheet | Additional info | Certificate | EU conformity |
| ExMax-30-F | 30 Nm | approx. 20 sec. / 90° | Open-close, 3-point |  | | | |
| ExMax-50-F | 50 Nm | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-60-F | 60 N·m | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-30-SF | 30 Nm | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-50-SF | 50 Nm | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-60-SF | 60 N·m | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-30-YF | 30 Nm | approx. 20 sec. / 90° | Modulating 0-10 V, 4-20 mA | | | | |
| ExMax-50-YF | 50 Nm | approx. 20 sec. / 90° | Modulating 0-10 V, 4-20 mA | | | | |
| ExMax-30-BF | 30 Nm | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-50-BF | 50 Nm | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-60-BF | 60 N·m | approx. 20 sec. / 90° | Open-close, 3-point | | | | |
| ExMax-30-F3 | 30 Nm | < 3 sec. / 90° | Open-close | | | | |
| ExMax-50-F3 | 50 Nm | < 3 sec. / 90° | Open-close | | | | |
| ExMax-30-SF3 | 30 Nm | < 3 sec. / 90° | Open-close | | | | |
| ExMax-50-SF3 | 50 Nm | < 3 sec. / 90° | Open-close | | | | |
| ExMax-30-BF3 | 30 Nm | < 3 sec. / 90° | Open-close | | | | |
| ExMax-50-BF3 | 50 Nm | < 3 sec. / 90° | Open-close | | | | |
ExMax-M | without spring return | 50…150 N·m | Zone 1, 2, 21, 22
| Type | Torque | Spring return | Control | Datasheet | Additional info | Certificate | EU conformity |
| ExMax-50.75 | 50/75 N·m | – | Open-close, 3-point | | | | |
| ExMax-100 | 100 N·m | – | Open-close, 3-point | | | | |
| ExMax-150 | 150 N·m | – | Open-close, 3-point | | | | |
| ExMax-50.75-S | 50/75 N·m | – | Open-close, 3-point | | | | |
| ExMax-100-S | 100 N·m | – | Open-close, 3-point | | | | |
| ExMax-150-S | 150 N·m | – | Open-close, 3-point | | | | |
| ExMax-50.75-Y | 50/75 N·m | – | Modulating 0-10 V, 4-20 mA | | | | |
| ExMax-100-Y | 100 N·m | – | Modulating 0-10 V, 4-20 mA | | | | |
Available variants
| Item name | Description | Item number |
| ExMax-50.75 | Open-close, 3-point | ExMax-50.75 |
| ExMax-50.75-S | As above with 2 integrated, potential-free switches (5°/85°) | ExMax-50.75-S |
| ExMax-50.75-CTM | As above with aluminum housing and seawater-resistant coating | ExMax-50.75-CTM |
| ExMax-50.75-VAM | As above with stainless steel housing for aggressive environments | ExMax-50.75-VAM |
| ExMax-50.75-S3 | Variant with 3 m cable | ExMax-50.75-S3 |
| ExMax-50.75-S38 | Ambient temperature up to +60 °C (T4), 110…240 VAC/DC, 25% ED, 3 m cable | ExMax-50.75-S38 |
Practical applications
In the first place, the ExMax-50.75 is ideal for safety dampers, ball valves, and butterfly valves in potentially explosive areas. In addition, the -S, CTM, and VAM options ensure precise adaptation to the environment. As a result, you minimize downtime while fully meeting compliance requirements.
FAQ
Under which ATEX zones can I use this actuator?
Zone 1, 2 (gas) and 21, 22 (dust), with markings Ex db [ib Gb] IIC T6/T5 and Ex tb [ib Db] IIIC T80/95 °C.
Which control types does the ExMax-50.75 support?
On-off and 3-point (floating). As a result, it fits into almost any HVAC control system.
Can I set the running time and torque myself?
Yes, via the 10-position switch you can select 40–150 s and 50 or 75 Nm; auto-setup calibrates the end positions.
Is there a version with auxiliary switches?
Yes, the -S variants have 2 potential-free auxiliary switches (5° and 85°).
What housing options are available?
Standard aluminum (IP67), optionally CTM (seawater-resistant coating) or VAM (stainless steel) for aggressive environments.
Are longer cable lengths available?
Yes, in addition to the standard cable (~1 m), variants with 3 m cable are available (S3 and S38).
Do you have any questions or would you like more information? Please contact us! You can reach us by phone, email or, if you prefer, via the chat function.
Scope of delivery – ExMax (size S or M)
1 × actuator with 1 m cable
1 × hex key for manual override
4 × screws for mounting
Special models – ExMax -…- BF (size S or M)
Actuators for fire dampers (ExMax -…- BF) + safety temperature switch ExPro-TT- ..
Special models in stainless steel – ExMax -…- VAS / VAM (size S or M)
Corrosion-resistant housing material in stainless steel comparable to AISI 316, some parts nickel-plated, screws in stainless steel Use under extreme weather or harsh climatic conditions
Special painted (coated) models – ExMax -…- CTS / CTM (size S or M)
Aluminum housing with seawater-resistant offshore / marine coating, resistant to corrosive and marine atmospheres, some parts nickel-plated, screws in stainless steel Suitable for offshore or onshore applications
Accessories / options – ExMax (size S or M)
- External adjustable, site-adjustable switches
- Mounting clamp for round damper shaft (only for ExMax size S)
- Ex-e junction box
- Adapters for butterfly or ball valves
- Mounting bracket
- Cable glands in nickel-plated brass
- Protective cover in stainless steel for mounting on ExMax actuators
- ExPolar heating system for use with ExMax actuators at low temperatures down to -50°C