diff --git a/machine_design/designs/computation.py b/machine_design/designs/computation.py
index 20b2d74..950ef8a 100644
--- a/machine_design/designs/computation.py
+++ b/machine_design/designs/computation.py
@@ -3,6 +3,7 @@
 from ansys.aedt.core import Maxwell2d
 
 from .geometry import GeometryBase
+from .reserved_variables import check_no_reserved_variable_names
 
 
 class ComputationBase(ABC):
@@ -13,6 +14,7 @@ def __init__(self, geometry: GeometryBase) -> None:
         self.set_solution_expressions()
         self.set_output_vars()
         self.set_post_params()
+        check_no_reserved_variable_names(self.oper_params, self.output_vars)
 
     @abstractmethod
     def set_oper_params(self): ...
diff --git a/machine_design/designs/geometry.py b/machine_design/designs/geometry.py
index 58d9dc2..37c34ad 100644
--- a/machine_design/designs/geometry.py
+++ b/machine_design/designs/geometry.py
@@ -4,6 +4,8 @@
 from ansys.aedt.core import Maxwell2d
 from ansys.aedt.core.modeler.modeler_2d import Modeler2D
 
+from .reserved_variables import check_no_reserved_variable_names
+
 
 class GeometryBase(ABC):
     def __init__(self) -> None:
@@ -15,6 +17,7 @@ def __init__(self) -> None:
         self.set_rot_points()
         self.set_derived_params()
         self.set_udp_par_list_stator()
+        check_no_reserved_variable_names(self.geom_params, self.wind_params, self.slot_params, self.mod_params)
 
     @abstractmethod
     def set_iron(self): ...
diff --git a/machine_design/designs/reserved_variables.py b/machine_design/designs/reserved_variables.py
new file mode 100644
index 0000000..397e1bc
--- /dev/null
+++ b/machine_design/designs/reserved_variables.py
@@ -0,0 +1,79 @@
+# Ansys intrinsic/reserved variable names
+reserved_variable_names = frozenset(
+    name.lower()
+    for name in (
+        "_Empty",
+        "_I1",
+        "_I2",
+        "_I3",
+        "_I4",
+        "_I5",
+        "_I6",
+        "_I7",
+        "_I8",
+        "_I9",
+        "_t",
+        "_u",
+        "_v",
+        "_V1",
+        "_V2",
+        "_V3",
+        "_V4",
+        "_V5",
+        "_V6",
+        "_V7",
+        "_V8",
+        "_V9",
+        "Ang",
+        "Budget_Index",
+        "Distance",
+        "ElectricalDegree",
+        "F",
+        "F1",
+        "F2",
+        "F3",
+        "FNoi",
+        "Freq",
+        "Hmax",
+        "Hmin",
+        "Ia",
+        "Ib",
+        "Index",
+        "IWavePhi",
+        "IWaveTheta",
+        "Normalized Deformation",
+        "Normalized Distance",
+        "OP",
+        "Pass",
+        "Phase",
+        "Phi",
+        "Position",
+        "R",
+        "Rho",
+        "RSpeed",
+        "Spectrum",
+        "Speed",
+        "Temp",
+        "Tend",
+        "Theta",
+        "Time",
+        "Time0",
+        "Vac",
+        "Vbe",
+        "Vce",
+        "Vds",
+        "Vgs",
+        "X",
+        "Y",
+        "Z",
+        "ZAng",
+        "ZRho",
+    )
+)
+
+
+def check_no_reserved_variable_names(*param_dicts: dict) -> None:
+    for params in param_dicts:
+        for name in params:
+            if name.lower() in reserved_variable_names:
+                raise ValueError(f"'{name}' is an Ansys intrinsic variable name and cannot be used as a design variable")
diff --git a/tests/test_computation.py b/tests/test_computation.py
new file mode 100644
index 0000000..f675f33
--- /dev/null
+++ b/tests/test_computation.py
@@ -0,0 +1,53 @@
+import pytest
+
+from machine_design.designs.computation import ComputationBase
+
+
+class _DummyComputation(ComputationBase):
+    def __init__(self, geometry, oper_params, output_vars):
+        self._oper_params = oper_params
+        self._output_vars = output_vars
+        super().__init__(geometry)
+
+    def set_oper_params(self):
+        self.oper_params = self._oper_params
+
+    def set_solution_expressions(self):
+        self.solution_expressions = "Moving1.Torque"
+
+    def set_output_vars(self):
+        self.output_vars = self._output_vars
+
+    def set_post_params(self):
+        self.post_params = {}
+
+    def assign_stator_coils(self, m2d):
+        pass
+
+    def inductance_computation(self, m2d):
+        pass
+
+    def set_variables(self, m2d, *args):
+        pass
+
+    def extract_results(self, solutions):
+        pass
+
+
+def test_no_reserved_names_does_not_raise():
+    _DummyComputation(object(), {"Im": "1A"}, {"pos": "Moving1.Position"})
+
+
+def test_reserved_name_in_oper_params_raises():
+    with pytest.raises(ValueError, match="F"):
+        _DummyComputation(object(), {"F": "50Hz"}, {})
+
+
+def test_reserved_name_in_output_vars_raises():
+    with pytest.raises(ValueError, match="Time"):
+        _DummyComputation(object(), {}, {"Time": "0s"})
+
+
+def test_reserved_name_check_is_case_insensitive():
+    with pytest.raises(ValueError, match="f"):
+        _DummyComputation(object(), {"f": "50Hz"}, {})
diff --git a/tests/test_geometry.py b/tests/test_geometry.py
new file mode 100644
index 0000000..df95e38
--- /dev/null
+++ b/tests/test_geometry.py
@@ -0,0 +1,58 @@
+import pytest
+
+from machine_design.designs.geometry import GeometryBase
+
+
+class _DummyGeometry(GeometryBase):
+    def __init__(self, geom_params, wind_params, slot_params, mod_params):
+        self._geom_params = geom_params
+        self._wind_params = wind_params
+        self._slot_params = slot_params
+        self._mod_params = mod_params
+        super().__init__()
+
+    def set_iron(self):
+        pass
+
+    def set_geom_params(self):
+        self.geom_params = self._geom_params
+
+    def set_slot_params(self):
+        self.slot_params = self._slot_params
+
+    def set_winds_params(self):
+        self.wind_params = self._wind_params
+
+    def set_mod_params(self):
+        self.mod_params = self._mod_params
+
+    def set_rot_points(self):
+        pass
+
+    def set_derived_params(self):
+        pass
+
+    def set_udp_par_list_stator(self):
+        pass
+
+    def build_stator(self, m2d):
+        pass
+
+
+def test_no_reserved_names_does_not_raise():
+    _DummyGeometry({"DiaStatorGap": "80mm"}, {"Nc": "10"}, {"Hs0": "1mm"}, {"Poles": "4"})
+
+
+def test_reserved_name_in_geom_params_raises():
+    with pytest.raises(ValueError, match="Distance"):
+        _DummyGeometry({"Distance": "80mm"}, {}, {}, {})
+
+
+def test_reserved_name_in_mod_params_raises():
+    with pytest.raises(ValueError, match="Time"):
+        _DummyGeometry({}, {}, {}, {"Time": "1s"})
+
+
+def test_reserved_name_check_is_case_insensitive():
+    with pytest.raises(ValueError, match="z"):
+        _DummyGeometry({}, {}, {"z": "1mm"}, {})